Re: ksoftirqd high cpu load on kernels 2.6.24 to 2.6.27-rc1-mm1

Re: ksoftirqd high cpu load on kernels 2.6.24 to 2.6.27-rc1-mm1

[Robert Hancock]

Dushan Tcholich wrote:
> Hello
> 
> This is my first bugreport on LKML so please be patient :)
> 
> top always shows me that ksoftirqd usualy gets around 8%CPU, it
> changes between 6 and 10%.
> It's sometimes ksoftirqd/0 sometimes /1, differs on the reboot but
> doesn't change during work.
> I noticed it because it had very high time+, 500hours or so.
> I reproduced these problems with kernels 2.6.24 .25 and .27-rc1-mm1. I
> don't remember that this happened during .22 and .23 kernels, but I
> can check again if it's necessary.
> Timer freq is 1000Hz
> 
> What I tried without changes with help from ##kernel:
> 1. built kernel without kvm;
> 2. disconnected all usb hw except mouse;
> 3. run glxgears which consumed 98% CPU and ksoftirqd  2%;
> 4. Tried to stress disk subsystem by copying a lot of small files on
> the same partition:
> time cp -R /usr/portage/* /tmp/1
> real 2m17.530s
> user 0m0.764s
> sys 0m18.596s
> 
> it was 127507 items 1.5GB, but just pdflush jumped to 14% from time to time;
> 5. disabled serial port in BIOS because my UPS was connected to it,
> and I suspected that it was maybe polling too much;
> 6. disconnected eth cable
> 7. tried googling but all I found is that some people had similar
> problem. Some TV cards were the culprit but I don't have that HW.
> 
> If you need any more data please cc me as I'm not subscribed

It would be useful to try running oprofile on an otherwise idle system 
and see where it reports the CPU time is being used..

Re: ksoftirqd high cpu load on kernels 2.6.24 to 2.6.27-rc1-mm1

[Dushan Tcholich]

Hello

On Mon, Aug 4, 2008 at 9:43 PM, Robert Hancock <hancockr@shaw.ca> wrote:
> Dushan Tcholich wrote:
>>
>> Hello
>>
>> This is my first bugreport on LKML so please be patient :)
>>
>> top always shows me that ksoftirqd usualy gets around 8%CPU, it
>> changes between 6 and 10%.
>> It's sometimes ksoftirqd/0 sometimes /1, differs on the reboot but
>> doesn't change during work.
>> I noticed it because it had very high time+, 500hours or so.
>> I reproduced these problems with kernels 2.6.24 .25 and .27-rc1-mm1. I
>> don't remember that this happened during .22 and .23 kernels, but I
>> can check again if it's necessary.
>> Timer freq is 1000Hz
>>
>> What I tried without changes with help from ##kernel:
>> 1. built kernel without kvm;
>> 2. disconnected all usb hw except mouse;
>> 3. run glxgears which consumed 98% CPU and ksoftirqd  2%;
>> 4. Tried to stress disk subsystem by copying a lot of small files on
>> the same partition:
>> time cp -R /usr/portage/* /tmp/1
>> real 2m17.530s
>> user 0m0.764s
>> sys 0m18.596s
>>
>> it was 127507 items 1.5GB, but just pdflush jumped to 14% from time to
>> time;
>> 5. disabled serial port in BIOS because my UPS was connected to it,
>> and I suspected that it was maybe polling too much;
>> 6. disconnected eth cable
>> 7. tried googling but all I found is that some people had similar
>> problem. Some TV cards were the culprit but I don't have that HW.
>>
>> If you need any more data please cc me as I'm not subscribed
>
> It would be useful to try running oprofile on an otherwise idle system and
> see where it reports the CPU time is being used..
>
I googled a little and found out that oprofile is a little above my head.
So as I thought that some driver or HW might be responsible for this I
tried to disable various onboard HW and found out that if I disable
onboard ethernet problem dissapears, so now I've added netdev and
maintainer of R8169 driver to cc.

Thanks
Dushan

Re: ksoftirqd high cpu load on kernels 2.6.24 to 2.6.27-rc1-mm1

[Francois Romieu]

Dushan Tcholich <dusanc@gmail.com> :
[...]
> I googled a little and found out that oprofile is a little above my head.
> So as I thought that some driver or HW might be responsible for this I
> tried to disable various onboard HW and found out that if I disable
> onboard ethernet problem dissapears, so now I've added netdev and
> maintainer of R8169 driver to cc.

Can you try 2.6.27-rc2 and send the content of /proc/interrupts, dmesg,
ifconfig as well as a capture of the strange output from top ?

It seems rather benign though.

-- 
Ueimor

Re: ksoftirqd high cpu load on kernels 2.6.24 to 2.6.27-rc1-mm1

[Dushan Tcholich]

Hi
Sorry for answering this late, but I was short on time and couldn't
get reiser4 to work with 2.6.27-rc2

On Thu, Aug 7, 2008 at 8:58 PM, Francois Romieu <romieu@fr.zoreil.com> wrote:
> Dushan Tcholich <dusanc@gmail.com> :
> [...]
>> I googled a little and found out that oprofile is a little above my head.
>> So as I thought that some driver or HW might be responsible for this I
>> tried to disable various onboard HW and found out that if I disable
>> onboard ethernet problem dissapears, so now I've added netdev and
>> maintainer of R8169 driver to cc.
>
> Can you try 2.6.27-rc2 and send the content of /proc/interrupts, dmesg,
> ifconfig as well as a capture of the strange output from top ?
>
I've copied my root to ext3 partition and with vanilla 2.6.27-rc2 I got:
-With my .config problem is still here
-With only rtl8169 removed from config there is no problem

> It seems rather benign though.
>
Well I wouldn't agree from power managment standpoint :). This nic is
in a lot of laptops.
8% of 2.13GHz Core2Duo CPU is a lot :)

Btw. should LKML be removed from cc?
If you need any more help please ask.
I hope I'm not harrasing you too much :)
> --
> Ueimor
>
Have a nice day
Dushan

Requested data:

top output:

top - 20:50:27 up 8 min,  3 users,  load average: 0.74, 0.45, 0.20
Tasks: 114 total,   1 running, 113 sleeping,   0 stopped,   0 zombie
Cpu(s):  2.8%us,  3.0%sy,  0.0%ni, 93.7%id,  0.0%wa,  0.2%hi,  0.3%si,  0.0%st
Mem:   1033720k total,   287288k used,   746432k free,     9860k buffers
Swap:   610460k total,        0k used,   610460k free,   129228k cached

  PID USER      PR  NI  VIRT  RES  SHR S %CPU %MEM    TIME+  COMMAND
    7 root      15  -5     0    0    0 S    8  0.0   0:37.75 ksoftirqd/1

Note the 8min uptime and ksoftirqd is already on 37min

cat /proc/interrupts
           CPU0       CPU1
  0:        126          0   IO-APIC-edge      timer
  1:       1042          0   IO-APIC-edge      i8042
  4:       1676          0   IO-APIC-edge      serial
  9:          0          0   IO-APIC-fasteoi   acpi
 16:      46224          0   IO-APIC-fasteoi   uhci_hcd:usb3,
radeon@pci:0000:01:00.0
 18:         21          0   IO-APIC-fasteoi   ehci_hcd:usb1, uhci_hcd:usb7
 19:      15440          0   IO-APIC-fasteoi   ata_piix, ata_piix, uhci_hcd:usb6
 21:       1269          0   IO-APIC-fasteoi   uhci_hcd:usb4, eth0
 22:        202          0   IO-APIC-fasteoi   HDA Intel
 23:         61          0   IO-APIC-fasteoi   ehci_hcd:usb2, uhci_hcd:usb5
NMI:          0          0   Non-maskable interrupts
LOC:     177598     165568   Local timer interrupts
RES:       1224       1729   Rescheduling interrupts
CAL:       1247       1548   function call interrupts
TLB:       1577       1848   TLB shootdowns
TRM:          0          0   Thermal event interrupts
SPU:          0          0   Spurious interrupts
ERR:          0
MIS:          0

ifconfig
br0       Link encap:Ethernet  HWaddr 00:16:17:92:D7:4C
          inet addr:192.168.1.3  Bcast:192.168.1.255  Mask:255.255.255.0
          UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
          RX packets:663 errors:0 dropped:0 overruns:0 frame:0
          TX packets:703 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:0
          RX bytes:216555 (211.4 Kb)  TX bytes:251971 (246.0 Kb)

eth0      Link encap:Ethernet  HWaddr 00:16:17:92:D7:4C
          UP BROADCAST RUNNING PROMISC MULTICAST  MTU:1500  Metric:1
          RX packets:663 errors:0 dropped:0 overruns:0 frame:0
          TX packets:703 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:1000
          RX bytes:225837 (220.5 Kb)  TX bytes:253009 (247.0 Kb)
          Interrupt:21 Base address:0xc000

lo        Link encap:Local Loopback
          inet addr:127.0.0.1  Mask:255.0.0.0
          UP LOOPBACK RUNNING  MTU:16436  Metric:1
          RX packets:407 errors:0 dropped:0 overruns:0 frame:0
          TX packets:407 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:0
          RX bytes:28589 (27.9 Kb)  TX bytes:28589 (27.9 Kb)


dmesg
Linux version 2.6.27-rc2 (root@krshina3) (gcc version 4.1.2 (Gentoo
4.1.2 p1.0.2)) #1 SMP Sun Aug 10 20:36:47 CEST 2008
BIOS-provided physical RAM map:
 BIOS-e820: 0000000000000000 - 000000000009f000 (usable)
 BIOS-e820: 000000000009f000 - 00000000000a0000 (reserved)
 BIOS-e820: 00000000000f0000 - 0000000000100000 (reserved)
 BIOS-e820: 0000000000100000 - 000000003fedf800 (usable)
 BIOS-e820: 000000003fedf800 - 000000003fee0000 (reserved)
 BIOS-e820: 000000003fee0000 - 000000003fee3000 (ACPI NVS)
 BIOS-e820: 000000003fee3000 - 000000003fef0000 (ACPI data)
 BIOS-e820: 000000003fef0000 - 000000003ff00000 (reserved)
 BIOS-e820: 00000000e0000000 - 00000000f0000000 (reserved)
 BIOS-e820: 00000000fec00000 - 0000000100000000 (reserved)
last_pfn = 0x3fedf max_arch_pfn = 0x100000
kernel direct mapping tables up to 38000000 @ 7000-c000
DMI 2.2 present.
ACPI: RSDP 000F91A0, 0014 (r0 IntelR)
ACPI: RSDT 3FEE3040, 0038 (r1 IntelR AWRDACPI 42302E31 AWRD        0)
ACPI: FACP 3FEE30C0, 0074 (r1 IntelR AWRDACPI 42302E31 AWRD        0)
ACPI: DSDT 3FEE3180, 4744 (r1 INTELR AWRDACPI     1000 MSFT  100000E)
ACPI: FACS 3FEE0000, 0040
ACPI: MCFG 3FEE7A40, 003C (r1 IntelR AWRDACPI 42302E31 AWRD        0)
ACPI: APIC 3FEE7940, 0084 (r1 IntelR AWRDACPI 42302E31 AWRD        0)
ACPI: SSDT 3FEE7AC0, 015C (r1  PmRef  Cpu0Ist     3000 INTL 20041203)
ACPI: SSDT 3FEE7F50, 02F1 (r1  PmRef    CpuPm     3000 INTL 20040311)
126MB HIGHMEM available.
896MB LOWMEM available.
  mapped low ram: 0 - 38000000
  low ram: 00000000 - 38000000
  bootmap 00008000 - 0000f000
(8 early reservations) ==> bootmem [0000000000 - 0038000000]
  #0 [0000000000 - 0000001000]   BIOS data page ==> [0000000000 - 0000001000]
  #1 [0000001000 - 0000002000]    EX TRAMPOLINE ==> [0000001000 - 0000002000]
  #2 [0000006000 - 0000007000]       TRAMPOLINE ==> [0000006000 - 0000007000]
  #3 [0000100000 - 0000545000]    TEXT DATA BSS ==> [0000100000 - 0000545000]
  #4 [0000545000 - 0000548000]    INIT_PG_TABLE ==> [0000545000 - 0000548000]
  #5 [000009f000 - 0000100000]    BIOS reserved ==> [000009f000 - 0000100000]
  #6 [0000007000 - 0000008000]          PGTABLE ==> [0000007000 - 0000008000]
  #7 [0000008000 - 000000f000]          BOOTMAP ==> [0000008000 - 000000f000]
Scan SMP from c0000000 for 1024 bytes.
Scan SMP from c009fc00 for 1024 bytes.
Scan SMP from c00f0000 for 65536 bytes.
found SMP MP-table at [c00f51d0] 000f51d0
Zone PFN ranges:
  DMA      0x00000000 -> 0x00001000
  Normal   0x00001000 -> 0x00038000
  HighMem  0x00038000 -> 0x0003fedf
Movable zone start PFN for each node
early_node_map[2] active PFN ranges
    0: 0x00000000 -> 0x0000009f
    0: 0x00000100 -> 0x0003fedf
On node 0 totalpages: 261758
free_area_init_node: node 0, pgdat c0474b40, node_mem_map c1000000
  DMA zone: 3967 pages, LIFO batch:0
  Normal zone: 223520 pages, LIFO batch:31
  HighMem zone: 32225 pages, LIFO batch:7
Using APIC driver default
ACPI: PM-Timer IO Port: 0x408
ACPI: Local APIC address 0xfee00000
ACPI: LAPIC (acpi_id[0x00] lapic_id[0x00] enabled)
ACPI: LAPIC (acpi_id[0x01] lapic_id[0x01] enabled)
ACPI: LAPIC (acpi_id[0x02] lapic_id[0x02] disabled)
ACPI: LAPIC (acpi_id[0x03] lapic_id[0x03] disabled)
ACPI: LAPIC_NMI (acpi_id[0x00] high edge lint[0x1])
ACPI: LAPIC_NMI (acpi_id[0x01] high edge lint[0x1])
ACPI: LAPIC_NMI (acpi_id[0x02] high edge lint[0x1])
ACPI: LAPIC_NMI (acpi_id[0x03] high edge lint[0x1])
ACPI: IOAPIC (id[0x04] address[0xfec00000] gsi_base[0])
IOAPIC[0]: apic_id 4, version 32, address 0xfec00000, GSI 0-23
ACPI: INT_SRC_OVR (bus 0 bus_irq 0 global_irq 2 dfl dfl)
ACPI: INT_SRC_OVR (bus 0 bus_irq 9 global_irq 9 high level)
ACPI: IRQ0 used by override.
ACPI: IRQ2 used by override.
ACPI: IRQ9 used by override.
Enabling APIC mode:  Flat.  Using 1 I/O APICs
Using ACPI (MADT) for SMP configuration information
mapped APIC to ffffb000 (fee00000)
mapped IOAPIC to ffffa000 (fec00000)
Allocating PCI resources starting at 40000000 (gap: 3ff00000:a0100000)
PERCPU: Allocating 28276 bytes of per cpu data
NR_CPUS: 2, nr_cpu_ids: 2, nr_node_ids 1
Built 1 zonelists in Zone order, mobility grouping on.  Total pages: 259712
Kernel command line: root=/dev/sdb1
Enabling fast FPU save and restore... done.
Enabling unmasked SIMD FPU exception support... done.
Initializing CPU#0
CPU 0 irqstacks, hard=c050f000 soft=c050d000
PID hash table entries: 4096 (order: 12, 16384 bytes)
TSC calibrated against PM_TIMER
Detected 2129.703 MHz processor.
Console: colour VGA+ 80x25
console [tty0] enabled
Dentry cache hash table entries: 131072 (order: 7, 524288 bytes)
Inode-cache hash table entries: 65536 (order: 6, 262144 bytes)
Memory: 1033120k/1047420k available (2594k kernel code, 13580k
reserved, 1265k data, 256k init, 129916k highmem)
virtual kernel memory layout:
    fixmap  : 0xfff9e000 - 0xfffff000   ( 388 kB)
    pkmap   : 0xff800000 - 0xffc00000   (4096 kB)
    vmalloc : 0xf8800000 - 0xff7fe000   ( 111 MB)
    lowmem  : 0xc0000000 - 0xf8000000   ( 896 MB)
      .init : 0xc04ca000 - 0xc050a000   ( 256 kB)
      .data : 0xc0388835 - 0xc04c4da0   (1265 kB)
      .text : 0xc0100000 - 0xc0388835   (2594 kB)
Checking if this processor honours the WP bit even in supervisor mode...Ok.
CPA: page pool initialized 1 of 1 pages preallocated
Calibrating delay loop (skipped), value calculated using timer
frequency.. 4259.40 BogoMIPS (lpj=2129703)
Mount-cache hash table entries: 512
CPU: L1 I cache: 32K, L1 D cache: 32K
CPU: L2 cache: 2048K
CPU: Physical Processor ID: 0
CPU: Processor Core ID: 0
Intel machine check architecture supported.
Intel machine check reporting enabled on CPU#0.
using mwait in idle threads.
Checking 'hlt' instruction... OK.
Freeing SMP alternatives: 14k freed
ACPI: Core revision 20080609
ENABLING IO-APIC IRQs
..TIMER: vector=0x31 apic1=0 pin1=2 apic2=-1 pin2=-1
CPU0: Intel(R) Core(TM)2 CPU          6400  @ 2.13GHz stepping 06
CPU 1 irqstacks, hard=c0510000 soft=c050e000
Booting processor 1/1 ip 6000
Initializing CPU#1
Calibrating delay using timer specific routine.. 4258.63 BogoMIPS (lpj=2129315)
CPU: L1 I cache: 32K, L1 D cache: 32K
CPU: L2 cache: 2048K
CPU: Physical Processor ID: 0
CPU: Processor Core ID: 1
Intel machine check architecture supported.
Intel machine check reporting enabled on CPU#1.
CPU1: Intel(R) Core(TM)2 CPU          6400  @ 2.13GHz stepping 06
checking TSC synchronization [CPU#0 -> CPU#1]: passed.
Brought up 2 CPUs
Total of 2 processors activated (8518.03 BogoMIPS).
CPU0 attaching sched-domain:
 domain 0: span 0-1 level MC
  groups: 0 1
CPU1 attaching sched-domain:
 domain 0: span 0-1 level MC
  groups: 1 0
net_namespace: 296 bytes
NET: Registered protocol family 16
No dock devices found.
ACPI: bus type pci registered
PCI: MCFG configuration 0: base e0000000 segment 0 buses 0 - 255
PCI: MCFG area at e0000000 reserved in E820
PCI: Using MMCONFIG for extended config space
PCI: Using configuration type 1 for base access
ACPI: EC: Look up EC in DSDT
ACPI: Interpreter enabled
ACPI: (supports S0 S5)
ACPI: Using IOAPIC for interrupt routing
ACPI: PCI Root Bridge [PCI0] (0000:00)
pci 0000:00:01.0: PME# supported from D0 D3hot D3cold
pci 0000:00:01.0: PME# disabled
pci 0000:00:1a.7: PME# supported from D0 D3hot D3cold
pci 0000:00:1a.7: PME# disabled
pci 0000:00:1b.0: PME# supported from D0 D3hot D3cold
pci 0000:00:1b.0: PME# disabled
pci 0000:00:1c.0: PME# supported from D0 D3hot D3cold
pci 0000:00:1c.0: PME# disabled
pci 0000:00:1d.7: PME# supported from D0 D3hot D3cold
pci 0000:00:1d.7: PME# disabled
pci 0000:00:1f.0: quirk: region 0400-047f claimed by ICH6 ACPI/GPIO/TCO
pci 0000:00:1f.0: quirk: region 0480-04bf claimed by ICH6 GPIO
pci 0000:00:1f.2: PME# supported from D3hot
pci 0000:00:1f.2: PME# disabled
pci 0000:00:1f.5: PME# supported from D3hot
pci 0000:00:1f.5: PME# disabled
pci 0000:01:00.0: supports D1
pci 0000:01:00.0: supports D2
pci 0000:01:00.1: supports D1
pci 0000:01:00.1: supports D2
pci 0000:03:06.0: supports D1
pci 0000:03:06.0: supports D2
pci 0000:03:06.0: PME# supported from D1 D2 D3hot D3cold
pci 0000:03:06.0: PME# disabled
pci 0000:00:1e.0: transparent bridge
bus 00 -> node 0
ACPI: PCI Interrupt Routing Table [\_SB_.PCI0._PRT]
ACPI: PCI Interrupt Routing Table [\_SB_.PCI0.PEX0._PRT]
ACPI: PCI Interrupt Routing Table [\_SB_.PCI0.HUB0._PRT]
ACPI: PCI Interrupt Link [LNKA] (IRQs 3 4 5 7 9 *10 11 14 15)
ACPI: PCI Interrupt Link [LNKB] (IRQs 3 4 5 7 *9 10 11 14 15)
ACPI: PCI Interrupt Link [LNKC] (IRQs *3 4 5 7 9 10 11 14 15)
ACPI: PCI Interrupt Link [LNKD] (IRQs 3 4 5 7 9 10 *11 14 15)
ACPI: PCI Interrupt Link [LNKE] (IRQs 3 4 5 7 9 10 11 14 15) *0, disabled.
ACPI: PCI Interrupt Link [LNKF] (IRQs 3 4 *5 7 9 10 11 14 15)
ACPI: PCI Interrupt Link [LNK0] (IRQs 3 4 5 *7 9 10 11 14 15)
ACPI: PCI Interrupt Link [LNK1] (IRQs 3 4 5 7 9 10 11 14 15) *0, disabled.
Linux Plug and Play Support v0.97 (c) Adam Belay
pnp: PnP ACPI init
ACPI: bus type pnp registered
pnp: PnP ACPI: found 13 devices
ACPI: ACPI bus type pnp unregistered
SCSI subsystem initialized
libata version 3.00 loaded.
usbcore: registered new interface driver usbfs
usbcore: registered new interface driver hub
usbcore: registered new device driver usb
PCI: Using ACPI for IRQ routing
system 00:01: ioport range 0x4d0-0x4d1 has been reserved
system 00:01: ioport range 0xa00-0xa7f has been reserved
system 00:01: ioport range 0x880-0x88f has been reserved
system 00:09: ioport range 0x400-0x4bf could not be reserved
system 00:0b: iomem range 0xe0000000-0xefffffff could not be reserved
system 00:0c: iomem range 0xf0000-0xf3fff could not be reserved
system 00:0c: iomem range 0xf4000-0xf7fff could not be reserved
system 00:0c: iomem range 0xf8000-0xfbfff could not be reserved
system 00:0c: iomem range 0xfc000-0xfffff could not be reserved
system 00:0c: iomem range 0x3fee0000-0x3fefffff could not be reserved
system 00:0c: iomem range 0x0-0x9ffff could not be reserved
system 00:0c: iomem range 0x100000-0x3fedffff could not be reserved
system 00:0c: iomem range 0xfec00000-0xfec00fff could not be reserved
system 00:0c: iomem range 0xfed14000-0xfed1dfff could not be reserved
system 00:0c: iomem range 0xfdffc000-0xfdffcbff has been reserved
system 00:0c: iomem range 0xfed20000-0xfed9ffff could not be reserved
system 00:0c: iomem range 0xfee00000-0xfee00fff could not be reserved
system 00:0c: iomem range 0xffb00000-0xffb7ffff could not be reserved
system 00:0c: iomem range 0xfff00000-0xffffffff could not be reserved
system 00:0c: iomem range 0xe0000-0xeffff has been reserved
pci 0000:00:01.0: PCI bridge, secondary bus 0000:01
pci 0000:00:01.0:   IO window: 0xd000-0xdfff
pci 0000:00:01.0:   MEM window: 0xfde00000-0xfdefffff
pci 0000:00:01.0:   PREFETCH window: 0x000000d0000000-0x000000dfffffff
pci 0000:00:1c.0: PCI bridge, secondary bus 0000:02
pci 0000:00:1c.0:   IO window: 0xb000-0xbfff
pci 0000:00:1c.0:   MEM window: 0xfdb00000-0xfdbfffff
pci 0000:00:1c.0:   PREFETCH window: 0x000000fda00000-0x000000fdafffff
pci 0000:00:1e.0: PCI bridge, secondary bus 0000:03
pci 0000:00:1e.0:   IO window: 0xc000-0xcfff
pci 0000:00:1e.0:   MEM window: 0xfdd00000-0xfddfffff
pci 0000:00:1e.0:   PREFETCH window: 0x000000fdc00000-0x000000fdcfffff
pci 0000:00:01.0: PCI INT A -> GSI 16 (level, low) -> IRQ 16
pci 0000:00:01.0: setting latency timer to 64
pci 0000:00:1c.0: PCI INT A -> GSI 16 (level, low) -> IRQ 16
pci 0000:00:1c.0: setting latency timer to 64
pci 0000:00:1e.0: setting latency timer to 64
NET: Registered protocol family 2
IP route cache hash table entries: 32768 (order: 5, 131072 bytes)
TCP established hash table entries: 131072 (order: 8, 1048576 bytes)
TCP bind hash table entries: 65536 (order: 7, 524288 bytes)
TCP: Hash tables configured (established 131072 bind 65536)
TCP reno registered
NET: Registered protocol family 1
highmem bounce pool size: 64 pages
Installing knfsd (copyright (C) 1996 okir@monad.swb.de).
NTFS driver 2.1.29 [Flags: R/W].
msgmni has been set to 1764
io scheduler noop registered
io scheduler cfq registered (default)
pci 0000:01:00.0: Boot video device
pcieport-driver 0000:00:01.0: setting latency timer to 64
pcieport-driver 0000:00:01.0: found MSI capability
pci_express 0000:00:01.0:pcie00: allocate port service
pci_express 0000:00:01.0:pcie03: allocate port service
pcieport-driver 0000:00:1c.0: setting latency timer to 64
pcieport-driver 0000:00:1c.0: found MSI capability
pci_express 0000:00:1c.0:pcie00: allocate port service
pci_express 0000:00:1c.0:pcie02: allocate port service
pci_express 0000:00:1c.0:pcie03: allocate port service
input: Power Button (FF) as /class/input/input0
ACPI: Power Button (FF) [PWRF]
input: Power Button (CM) as /class/input/input1
ACPI: Power Button (CM) [PWRB]
fan PNP0C0B:00: registered as cooling_device0
ACPI: Fan [FAN] (on)
processor ACPI0007:00: registered as cooling_device1
ACPI: SSDT 3FEE7EC0, 0087 (r1  PmRef  Cpu1Ist     3000 INTL 20041203)
processor ACPI0007:01: registered as cooling_device2
thermal LNXTHERM:01: registered as thermal_zone0
ACPI: Thermal Zone [THRM] (46 C)
Real Time Clock Driver v1.12ac
Linux agpgart interface v0.103
Hangcheck: starting hangcheck timer 0.9.0 (tick is 180 seconds, margin
is 60 seconds).
Hangcheck: Using get_cycles().
[drm] Initialized drm 1.1.0 20060810
pci 0000:01:00.0: PCI INT A -> GSI 16 (level, low) -> IRQ 16
pci 0000:01:00.0: setting latency timer to 64
[drm] Initialized radeon 1.29.0 20080528 on minor 0
Serial: 8250/16550 driver4 ports, IRQ sharing disabled
serial8250: ttyS0 at I/O 0x3f8 (irq = 4) is a 16550A
00:07: ttyS0 at I/O 0x3f8 (irq = 4) is a 16550A
brd: module loaded
loop: module loaded
tun: Universal TUN/TAP device driver, 1.6
tun: (C) 1999-2004 Max Krasnyansky <maxk@qualcomm.com>
r8169 Gigabit Ethernet driver 2.3LK-NAPI loaded
r8169 0000:03:06.0: PCI INT A -> GSI 21 (level, low) -> IRQ 21
eth0: RTL8169sc/8110sc at 0xf881c000, 00:16:17:92:d7:4c, XID 18000000 IRQ 21
Driver 'sd' needs updating - please use bus_type methods
Driver 'sr' needs updating - please use bus_type methods
ata_piix 0000:00:1f.2: version 2.12
ata_piix 0000:00:1f.2: PCI INT B -> GSI 19 (level, low) -> IRQ 19
ata_piix 0000:00:1f.2: MAP [ P0 P2 P1 P3 ]
ata_piix 0000:00:1f.2: setting latency timer to 64
scsi0 : ata_piix
scsi1 : ata_piix
ata1: SATA max UDMA/133 cmd 0xfa00 ctl 0xf900 bmdma 0xf600 irq 19
ata2: SATA max UDMA/133 cmd 0xf800 ctl 0xf700 bmdma 0xf608 irq 19
Switched to high resolution mode on CPU 1
Switched to high resolution mode on CPU 0
ata1: SATA link up 1.5 Gbps (SStatus 113 SControl 300)
ata1.00: ATA-7: WDC WD740ADFD-00NLR1, 20.07P20, max UDMA/133
ata1.00: 145226112 sectors, multi 16: LBA48 NCQ (not used)
ata1.00: configured for UDMA/133
ata2: SATA link up 3.0 Gbps (SStatus 123 SControl 300)
ata2.00: ATA-8: WDC WD5000AAKS-00A7B0, 01.03B01, max UDMA/133
ata2.00: 976773168 sectors, multi 16: LBA48 NCQ (depth 0/32)
ata2.00: configured for UDMA/133
scsi 0:0:0:0: Direct-Access     ATA      WDC WD740ADFD-00 20.0 PQ: 0 ANSI: 5
sd 0:0:0:0: [sda] 145226112 512-byte hardware sectors (74356 MB)
sd 0:0:0:0: [sda] Write Protect is off
sd 0:0:0:0: [sda] Mode Sense: 00 3a 00 00
sd 0:0:0:0: [sda] Write cache: enabled, read cache: enabled, doesn't
support DPO or FUA
sd 0:0:0:0: [sda] 145226112 512-byte hardware sectors (74356 MB)
sd 0:0:0:0: [sda] Write Protect is off
sd 0:0:0:0: [sda] Mode Sense: 00 3a 00 00
sd 0:0:0:0: [sda] Write cache: enabled, read cache: enabled, doesn't
support DPO or FUA
 sda: sda1 sda2 sda3 sda4
sd 0:0:0:0: [sda] Attached SCSI disk
sd 0:0:0:0: Attached scsi generic sg0 type 0
scsi 1:0:0:0: Direct-Access     ATA      WDC WD5000AAKS-0 01.0 PQ: 0 ANSI: 5
sd 1:0:0:0: [sdb] 976773168 512-byte hardware sectors (500108 MB)
sd 1:0:0:0: [sdb] Write Protect is off
sd 1:0:0:0: [sdb] Mode Sense: 00 3a 00 00
sd 1:0:0:0: [sdb] Write cache: enabled, read cache: enabled, doesn't
support DPO or FUA
sd 1:0:0:0: [sdb] 976773168 512-byte hardware sectors (500108 MB)
sd 1:0:0:0: [sdb] Write Protect is off
sd 1:0:0:0: [sdb] Mode Sense: 00 3a 00 00
sd 1:0:0:0: [sdb] Write cache: enabled, read cache: enabled, doesn't
support DPO or FUA
 sdb: sdb1
sd 1:0:0:0: [sdb] Attached SCSI disk
sd 1:0:0:0: Attached scsi generic sg1 type 0
ata_piix 0000:00:1f.5: PCI INT B -> GSI 19 (level, low) -> IRQ 19
ata_piix 0000:00:1f.5: MAP [ P0 -- P1 -- ]
ata_piix 0000:00:1f.5: setting latency timer to 64
scsi2 : ata_piix
scsi3 : ata_piix
ata3: SATA max UDMA/133 cmd 0xf300 ctl 0xf200 bmdma 0xef00 irq 19
ata4: SATA max UDMA/133 cmd 0xf100 ctl 0xf000 bmdma 0xef08 irq 19
ata3: SATA link up 1.5 Gbps (SStatus 113 SControl 300)
ata3.00: ATAPI: TSSTcorpCD/DVDW SH-W163A, TS01, max UDMA/33
ata3.00: applying bridge limits
ata3.00: configured for UDMA/33
ata4: SATA link down (SStatus 0 SControl 300)
scsi 2:0:0:0: CD-ROM            TSSTcorp CD/DVDW SH-W163A TS01 PQ: 0 ANSI: 5
sr0: scsi3-mmc drive: 24x/24x writer cd/rw xa/form2 cdda tray
Uniform CD-ROM driver Revision: 3.20
sr 2:0:0:0: Attached scsi CD-ROM sr0
sr 2:0:0:0: Attached scsi generic sg2 type 5
ehci_hcd 0000:00:1a.7: PCI INT C -> GSI 18 (level, low) -> IRQ 18
ehci_hcd 0000:00:1a.7: setting latency timer to 64
ehci_hcd 0000:00:1a.7: EHCI Host Controller
ehci_hcd 0000:00:1a.7: new USB bus registered, assigned bus number 1
ehci_hcd 0000:00:1a.7: cache line size of 32 is not supported
ehci_hcd 0000:00:1a.7: irq 18, io mem 0xfdfff000
ehci_hcd 0000:00:1a.7: USB 2.0 started, EHCI 1.00, driver 10 Dec 2004
usb usb1: configuration #1 chosen from 1 choice
hub 1-0:1.0: USB hub found
hub 1-0:1.0: 4 ports detected
ehci_hcd 0000:00:1d.7: PCI INT A -> GSI 23 (level, low) -> IRQ 23
ehci_hcd 0000:00:1d.7: setting latency timer to 64
ehci_hcd 0000:00:1d.7: EHCI Host Controller
ehci_hcd 0000:00:1d.7: new USB bus registered, assigned bus number 2
ehci_hcd 0000:00:1d.7: cache line size of 32 is not supported
ehci_hcd 0000:00:1d.7: irq 23, io mem 0xfdffe000
usb 1-2: new high speed USB device using ehci_hcd and address 2
ehci_hcd 0000:00:1d.7: USB 2.0 started, EHCI 1.00, driver 10 Dec 2004
usb usb2: configuration #1 chosen from 1 choice
hub 2-0:1.0: USB hub found
hub 2-0:1.0: 6 ports detected
usb 1-2: configuration #1 chosen from 1 choice
ohci_hcd: 2006 August 04 USB 1.1 'Open' Host Controller (OHCI) Driver
USB Universal Host Controller Interface driver v3.0
uhci_hcd 0000:00:1a.0: PCI INT A -> GSI 16 (level, low) -> IRQ 16
uhci_hcd 0000:00:1a.0: setting latency timer to 64
uhci_hcd 0000:00:1a.0: UHCI Host Controller
uhci_hcd 0000:00:1a.0: new USB bus registered, assigned bus number 3
uhci_hcd 0000:00:1a.0: irq 16, io base 0x0000ff00
usb usb3: configuration #1 chosen from 1 choice
hub 3-0:1.0: USB hub found
hub 3-0:1.0: 2 ports detected
uhci_hcd 0000:00:1a.1: PCI INT B -> GSI 21 (level, low) -> IRQ 21
uhci_hcd 0000:00:1a.1: setting latency timer to 64
uhci_hcd 0000:00:1a.1: UHCI Host Controller
uhci_hcd 0000:00:1a.1: new USB bus registered, assigned bus number 4
uhci_hcd 0000:00:1a.1: irq 21, io base 0x0000fe00
usb usb4: configuration #1 chosen from 1 choice
hub 4-0:1.0: USB hub found
hub 4-0:1.0: 2 ports detected
usb 2-5: new high speed USB device using ehci_hcd and address 4
uhci_hcd 0000:00:1d.0: PCI INT A -> GSI 23 (level, low) -> IRQ 23
uhci_hcd 0000:00:1d.0: setting latency timer to 64
uhci_hcd 0000:00:1d.0: UHCI Host Controller
uhci_hcd 0000:00:1d.0: new USB bus registered, assigned bus number 5
uhci_hcd 0000:00:1d.0: irq 23, io base 0x0000fd00
usb usb5: configuration #1 chosen from 1 choice
hub 5-0:1.0: USB hub found
hub 5-0:1.0: 2 ports detected
usb 2-5: configuration #1 chosen from 1 choice
hub 2-5:1.0: USB hub found
hub 2-5:1.0: 4 ports detected
uhci_hcd 0000:00:1d.1: PCI INT B -> GSI 19 (level, low) -> IRQ 19
uhci_hcd 0000:00:1d.1: setting latency timer to 64
uhci_hcd 0000:00:1d.1: UHCI Host Controller
uhci_hcd 0000:00:1d.1: new USB bus registered, assigned bus number 6
uhci_hcd 0000:00:1d.1: irq 19, io base 0x0000fc00
usb usb6: configuration #1 chosen from 1 choice
hub 6-0:1.0: USB hub found
hub 6-0:1.0: 2 ports detected
usb 5-2: new low speed USB device using uhci_hcd and address 2
uhci_hcd 0000:00:1d.2: PCI INT C -> GSI 18 (level, low) -> IRQ 18
uhci_hcd 0000:00:1d.2: setting latency timer to 64
uhci_hcd 0000:00:1d.2: UHCI Host Controller
uhci_hcd 0000:00:1d.2: new USB bus registered, assigned bus number 7
uhci_hcd 0000:00:1d.2: irq 18, io base 0x0000fb00
usb usb7: configuration #1 chosen from 1 choice
hub 7-0:1.0: USB hub found
hub 7-0:1.0: 2 ports detected
usb 5-2: configuration #1 chosen from 1 choice
usb 6-1: new low speed USB device using uhci_hcd and address 2
Initializing USB Mass Storage driver...
usb 6-1: configuration #1 chosen from 1 choice
usbcore: registered new interface driver usb-storage
USB Mass Storage support registered.
PNP: PS/2 Controller [PNP0303:PS2K] at 0x60,0x64 irq 1
PNP: PS/2 appears to have AUX port disabled, if this is incorrect
please boot with i8042.nopnp
serio: i8042 KBD port at 0x60,0x64 irq 1
mice: PS/2 mouse device common for all mice
coretemp coretemp.0: Using relative temperature scale!
coretemp coretemp.1: Using relative temperature scale!
input: AT Translated Set 2 keyboard as /class/input/input2
input: 5-Axis,12-Button with POV  as /class/input/input3
input: USB HID v1.10 Joystick [5-Axis,12-Button with POV ] on usb-0000:00:1d.0-2
input: Logitech USB-PS/2 Optical Mouse as /class/input/input4
input: USB HID v1.10 Mouse [Logitech USB-PS/2 Optical Mouse] on
usb-0000:00:1d.1-1
usbcore: registered new interface driver usbhid
usbhid: v2.6:USB HID core driver
Advanced Linux Sound Architecture Driver Version 1.0.17.
HDA Intel 0000:00:1b.0: PCI INT A -> GSI 22 (level, low) -> IRQ 22
HDA Intel 0000:00:1b.0: setting latency timer to 64
hda_codec: Unknown model for ALC883, trying auto-probe from BIOS...
ALSA device list:
  #0: HDA Intel at 0xfdff8000 irq 22
TCP cubic registered
NET: Registered protocol family 17
RPC: Registered udp transport module.
RPC: Registered tcp transport module.
Starting balanced_irq
Using IPI Shortcut mode
kjournald starting.  Commit interval 5 seconds
EXT3-fs: mounted filesystem with ordered data mode.
VFS: Mounted root (ext3 filesystem) readonly.
Freeing unused kernel memory: 256k freed
EXT3 FS on sdb1, internal journal
kjournald starting.  Commit interval 5 seconds
EXT3 FS on sda4, internal journal
EXT3-fs: mounted filesystem with ordered data mode.
Adding 610460k swap on /dev/sda3.  Priority:-1 extents:1 across:610460k
r8169: eth0: link up
br0: Dropping NETIF_F_UFO since no NETIF_F_HW_CSUM feature.
device eth0 entered promiscuous mode
br0: topology change detected, propagating
br0: port 1(eth0) entering forwarding state
[drm] Setting GART location based on new memory map
[drm] Loading R400 Microcode
[drm] Num pipes: 4
[drm] writeback test succeeded in 1 usecs
warning: `ntpd' uses 32-bit capabilities (legacy support in use)
[drm] Num pipes: 4
[drm] Loading R400 Microcode
[drm] Num pipes: 4
ISO 9660 Extensions: Microsoft Joliet Level 3
ISO 9660 Extensions: RRIP_1991A
[drm] Num pipes: 4
[drm] Loading R400 Microcode
[drm] Num pipes: 4

Re: ksoftirqd high cpu load on kernels 2.6.24 to 2.6.27-rc1-mm1

[Dushan Tcholich]

Hi

On Sun, Aug 10, 2008 at 9:00 PM, Dushan Tcholich <dusanc@gmail.com> wrote:
> Hi
> Sorry for answering this late, but I was short on time and couldn't
> get reiser4 to work with 2.6.27-rc2
>
> On Thu, Aug 7, 2008 at 8:58 PM, Francois Romieu <romieu@fr.zoreil.com> wrote:
>> Dushan Tcholich <dusanc@gmail.com> :
>> [...]
>>> I googled a little and found out that oprofile is a little above my head.
>>> So as I thought that some driver or HW might be responsible for this I
>>> tried to disable various onboard HW and found out that if I disable
>>> onboard ethernet problem dissapears, so now I've added netdev and
>>> maintainer of R8169 driver to cc.
>>
>> Can you try 2.6.27-rc2 and send the content of /proc/interrupts, dmesg,
>> ifconfig as well as a capture of the strange output from top ?
>>

I tried some more kernels and I had the same problem with 2.6.23.17
and 2.6.27-rc1-mm1, but I couldn't reproduce it with kernel from
sysresccd 1.0.1 http://www.sysresccd.org/ which is a patched version
of 2.6.24 i think .7 when I booted it to change fs.
Could it be that something in userspace is creating this?

> I've copied my root to ext3 partition and with vanilla 2.6.27-rc2 I got:
> -With my .config problem is still here
> -With only rtl8169 removed from config there is no problem
>
>> It seems rather benign though.
>>
> Well I wouldn't agree from power managment standpoint :). This nic is
> in a lot of laptops.
> 8% of 2.13GHz Core2Duo CPU is a lot :)
>
> Btw. should LKML be removed from cc?
> If you need any more help please ask.
> I hope I'm not harrasing you too much :)
>> --
>> Ueimor
>>
> Have a nice day
> Dushan
>
...

Re: ksoftirqd high cpu load on kernels 2.6.24 to 2.6.27-rc1-mm1

[Dushan Tcholich]

Hello again


On Mon, Aug 11, 2008 at 9:53 AM, Dushan Tcholich <dusanc@gmail.com> wrote:
> Hi
>
> On Sun, Aug 10, 2008 at 9:00 PM, Dushan Tcholich <dusanc@gmail.com> wrote:
>> Hi
>> Sorry for answering this late, but I was short on time and couldn't
>> get reiser4 to work with 2.6.27-rc2
>>
>> On Thu, Aug 7, 2008 at 8:58 PM, Francois Romieu <romieu@fr.zoreil.com> wrote:
>>> Dushan Tcholich <dusanc@gmail.com> :
>>> [...]
>>>> I googled a little and found out that oprofile is a little above my head.
>>>> So as I thought that some driver or HW might be responsible for this I
>>>> tried to disable various onboard HW and found out that if I disable
>>>> onboard ethernet problem dissapears, so now I've added netdev and
>>>> maintainer of R8169 driver to cc.
>>>
>>> Can you try 2.6.27-rc2 and send the content of /proc/interrupts, dmesg,
>>> ifconfig as well as a capture of the strange output from top ?
>>>
>
> I tried some more kernels and I had the same problem with 2.6.23.17
> and 2.6.27-rc1-mm1, but I couldn't reproduce it with kernel from
> sysresccd 1.0.1 http://www.sysresccd.org/ which is a patched version
> of 2.6.24 i think .7 when I booted it to change fs.
> Could it be that something in userspace is creating this?
>

I dug a little more and found out some new info.
Unsolved bugreport with same symptoms:
http://marc.info/?l=linux-kernel&m=119613299024398&w=2
Problems appear if I start br0 interface, as context switch rate
increases 200 times. If I start eth0 instead everything looks ok.
The bugreport above had bridging enabled too.

When using eth0 I get:
 vmstat -n 1 10
procs -----------memory---------- ---swap-- -----io---- -system-- ----cpu----
 r  b   swpd   free   buff  cache   si   so    bi    bo   in   cs us sy id wa
 2  0  17720 162288  25024 576852    0    0    21    22    6    9 10  4 85  0
 0  0  17720 162196  25024 576880    0    0     0     0   13  473  0  0 99  0
 0  0  17720 162196  25028 576880    0    0     0     4   36 1122  1  0 99  0
 0  0  17720 162196  25028 576880    0    0     0     0   83  844  0  0 99  0
 0  0  17720 162196  25028 576880    0    0     0     0   55  691  1  0 99  0
 0  0  17720 162556  25028 576880    0    0     0     0   13  490  1  0 100  0
 0  0  17720 162100  25028 576880    0    0     0     0   39  561  6  0 94  0
 1  0  17720 162028  25028 576880    0    0     0     0   16 1030  4  0 96  0
 0  0  17720 162028  25028 576880    0    0     0     0   40  597  1  0 99  0
 0  0  17720 162028  25028 576880    0    0     0     0   12  512  2  0 97  0

 top

top - 03:30:07 up 6 days,  5:40,  4 users,  load average: 0.02, 0.11, 0.28
Tasks: 149 total,   2 running, 147 sleeping,   0 stopped,   0 zombie
Cpu(s): 12.1%us,  3.3%sy,  0.0%ni, 84.6%id,  0.0%wa,  0.0%hi,  0.0%si,  0.0%st
Mem:   1033388k total,   871336k used,   162052k free,    25016k buffers
Swap:   610460k total,    17720k used,   592740k free,   576852k cached

  PID USER      PR  NI  VIRT  RES  SHR S %CPU %MEM    TIME+  COMMAND

    4 root      15  -5     0    0    0 S    0  0.0 554:23.44 ksoftirqd/0

If I use br0 I get:
 vmstat -n 1 10
procs -----------memory---------- ---swap-- -----io---- -system-- ----cpu----
 r  b   swpd   free   buff  cache   si   so    bi    bo   in   cs us sy id wa
 0  0  17720 162112  25048 577120    0    0    21    22    6   11 10  4 86  0
 0  0  17720 162152  25048 577120    0    0     0     0   14 111082  0  3 97  0
 0  0  17720 162152  25048 577120    0    0     0     0   23 107134  1  3 96  0
 1  0  17720 160148  25048 577120    0    0     0     0   11 109888  2  3 95  0
 0  0  17720 162032  25048 577120    0    0     0     0   33 108163  1  2 97  0
 0  0  17720 162032  25048 577120    0    0     0     0    7 104642  2  2 95  0
 0  0  17720 162020  25048 577120    0    0     0     0   41 109135  0  2 98  0
 0  0  17720 162036  25048 577120    0    0     0     0    9 105133  0  3 96  0
 0  0  17720 162020  25048 577120    0    0     0     0   42 107605  1  2 97  0
 1  0  17720 162032  25048 577120    0    0     0     0    5 110768  0  2 98  0

top

top - 03:32:03 up 6 days,  5:41,  4 users,  load average: 0.09, 0.10, 0.26
Tasks: 148 total,   2 running, 146 sleeping,   0 stopped,   0 zombie
Cpu(s):  4.8%us,  2.0%sy,  0.0%ni, 93.0%id,  0.0%wa,  0.0%hi,  0.2%si,  0.0%st
Mem:   1033388k total,   871564k used,   161824k free,    25048k buffers
Swap:   610460k total,    17720k used,   592740k free,   577120k cached

  PID USER      PR  NI  VIRT  RES  SHR S %CPU %MEM    TIME+  COMMAND
11489 dusan     20   0  235m  85m  24m R    6  8.5   1:03.51 firefox
    4 root      15  -5     0    0    0 S   7  0.0 554:24.04 ksoftirqd/0

I start br0 like this in /etc/conf.d/net

bridge_br0="eth0"
config_eth0=( "null" )
config_br0=( "192.168.1.3/24" )
RC_NEED_br0="net.eth0"
brctl_br0=( "setfd 0" "sethello 0" "stp off" )
#routes_br0=( "default gw 192.168.1.3" )
depend_br0() {
        need net.eth0
}

I start eth0 like this in /etc/conf.d/net
config_eth0=( "192.168.1.3/24" )

>> I've copied my root to ext3 partition and with vanilla 2.6.27-rc2 I got:
>> -With my .config problem is still here
>> -With only rtl8169 removed from config there is no problem
>>
>>> It seems rather benign though.
>>>
>> Well I wouldn't agree from power managment standpoint :). This nic is
>> in a lot of laptops.
>> 8% of 2.13GHz Core2Duo CPU is a lot :)
>>
>> Btw. should LKML be removed from cc?
>> If you need any more help please ask.
>> I hope I'm not harrasing you too much :)
>>> --
>>> Ueimor
>>>
>> Have a nice day
>> Dushan
>>
> ...
>
Have a nice day
Dushan

Re: ksoftirqd high cpu load on kernels 2.6.24 to 2.6.27-rc1-mm1

[Dushan Tcholich]

Hello
I found the culprit.

When using powertop I get:
Top causes for wakeups:
  35,2% (251,0)                ip : br_stp_enable_bridge (br_hello_timer_expired

So I tried to turn them off with:
brctl sethello br0 0
but the problem persisted.
If I do
brctl sethello br0 5
context switch rate drops 200 times and problem is gone.
I think that the command brctl sethello br0 0 doesn't turn off hello
messages, but sends them 250 times per second.

Thanks for your time
Dushan
On Sat, Aug 30, 2008 at 3:48 AM, Dushan Tcholich <dusanc@gmail.com> wrote:
> Hello again
>
>
> On Mon, Aug 11, 2008 at 9:53 AM, Dushan Tcholich <dusanc@gmail.com> wrote:
>> Hi
>>
>> On Sun, Aug 10, 2008 at 9:00 PM, Dushan Tcholich <dusanc@gmail.com> wrote:
>>> Hi
>>> Sorry for answering this late, but I was short on time and couldn't
>>> get reiser4 to work with 2.6.27-rc2
>>>
>>> On Thu, Aug 7, 2008 at 8:58 PM, Francois Romieu <romieu@fr.zoreil.com> wrote:
>>>> Dushan Tcholich <dusanc@gmail.com> :
>>>> [...]
>>>>> I googled a little and found out that oprofile is a little above my head.
>>>>> So as I thought that some driver or HW might be responsible for this I
>>>>> tried to disable various onboard HW and found out that if I disable
>>>>> onboard ethernet problem dissapears, so now I've added netdev and
>>>>> maintainer of R8169 driver to cc.
>>>>
>>>> Can you try 2.6.27-rc2 and send the content of /proc/interrupts, dmesg,
>>>> ifconfig as well as a capture of the strange output from top ?
>>>>
>>
>> I tried some more kernels and I had the same problem with 2.6.23.17
>> and 2.6.27-rc1-mm1, but I couldn't reproduce it with kernel from
>> sysresccd 1.0.1 http://www.sysresccd.org/ which is a patched version
>> of 2.6.24 i think .7 when I booted it to change fs.
>> Could it be that something in userspace is creating this?
>>
>
> I dug a little more and found out some new info.
> Unsolved bugreport with same symptoms:
> http://marc.info/?l=linux-kernel&m=119613299024398&w=2
> Problems appear if I start br0 interface, as context switch rate
> increases 200 times. If I start eth0 instead everything looks ok.
> The bugreport above had bridging enabled too.
>
> When using eth0 I get:
>  vmstat -n 1 10
> procs -----------memory---------- ---swap-- -----io---- -system-- ----cpu----
>  r  b   swpd   free   buff  cache   si   so    bi    bo   in   cs us sy id wa
>  2  0  17720 162288  25024 576852    0    0    21    22    6    9 10  4 85  0
>  0  0  17720 162196  25024 576880    0    0     0     0   13  473  0  0 99  0
>  0  0  17720 162196  25028 576880    0    0     0     4   36 1122  1  0 99  0
>  0  0  17720 162196  25028 576880    0    0     0     0   83  844  0  0 99  0
>  0  0  17720 162196  25028 576880    0    0     0     0   55  691  1  0 99  0
>  0  0  17720 162556  25028 576880    0    0     0     0   13  490  1  0 100  0
>  0  0  17720 162100  25028 576880    0    0     0     0   39  561  6  0 94  0
>  1  0  17720 162028  25028 576880    0    0     0     0   16 1030  4  0 96  0
>  0  0  17720 162028  25028 576880    0    0     0     0   40  597  1  0 99  0
>  0  0  17720 162028  25028 576880    0    0     0     0   12  512  2  0 97  0
>
>  top
>
> top - 03:30:07 up 6 days,  5:40,  4 users,  load average: 0.02, 0.11, 0.28
> Tasks: 149 total,   2 running, 147 sleeping,   0 stopped,   0 zombie
> Cpu(s): 12.1%us,  3.3%sy,  0.0%ni, 84.6%id,  0.0%wa,  0.0%hi,  0.0%si,  0.0%st
> Mem:   1033388k total,   871336k used,   162052k free,    25016k buffers
> Swap:   610460k total,    17720k used,   592740k free,   576852k cached
>
>  PID USER      PR  NI  VIRT  RES  SHR S %CPU %MEM    TIME+  COMMAND
>
>    4 root      15  -5     0    0    0 S    0  0.0 554:23.44 ksoftirqd/0
>
> If I use br0 I get:
>  vmstat -n 1 10
> procs -----------memory---------- ---swap-- -----io---- -system-- ----cpu----
>  r  b   swpd   free   buff  cache   si   so    bi    bo   in   cs us sy id wa
>  0  0  17720 162112  25048 577120    0    0    21    22    6   11 10  4 86  0
>  0  0  17720 162152  25048 577120    0    0     0     0   14 111082  0  3 97  0
>  0  0  17720 162152  25048 577120    0    0     0     0   23 107134  1  3 96  0
>  1  0  17720 160148  25048 577120    0    0     0     0   11 109888  2  3 95  0
>  0  0  17720 162032  25048 577120    0    0     0     0   33 108163  1  2 97  0
>  0  0  17720 162032  25048 577120    0    0     0     0    7 104642  2  2 95  0
>  0  0  17720 162020  25048 577120    0    0     0     0   41 109135  0  2 98  0
>  0  0  17720 162036  25048 577120    0    0     0     0    9 105133  0  3 96  0
>  0  0  17720 162020  25048 577120    0    0     0     0   42 107605  1  2 97  0
>  1  0  17720 162032  25048 577120    0    0     0     0    5 110768  0  2 98  0
>
> top
>
> top - 03:32:03 up 6 days,  5:41,  4 users,  load average: 0.09, 0.10, 0.26
> Tasks: 148 total,   2 running, 146 sleeping,   0 stopped,   0 zombie
> Cpu(s):  4.8%us,  2.0%sy,  0.0%ni, 93.0%id,  0.0%wa,  0.0%hi,  0.2%si,  0.0%st
> Mem:   1033388k total,   871564k used,   161824k free,    25048k buffers
> Swap:   610460k total,    17720k used,   592740k free,   577120k cached
>
>  PID USER      PR  NI  VIRT  RES  SHR S %CPU %MEM    TIME+  COMMAND
> 11489 dusan     20   0  235m  85m  24m R    6  8.5   1:03.51 firefox
>    4 root      15  -5     0    0    0 S   7  0.0 554:24.04 ksoftirqd/0
>
> I start br0 like this in /etc/conf.d/net
>
> bridge_br0="eth0"
> config_eth0=( "null" )
> config_br0=( "192.168.1.3/24" )
> RC_NEED_br0="net.eth0"
> brctl_br0=( "setfd 0" "sethello 0" "stp off" )
> #routes_br0=( "default gw 192.168.1.3" )
> depend_br0() {
>        need net.eth0
> }
>
> I start eth0 like this in /etc/conf.d/net
> config_eth0=( "192.168.1.3/24" )
>
>>> I've copied my root to ext3 partition and with vanilla 2.6.27-rc2 I got:
>>> -With my .config problem is still here
>>> -With only rtl8169 removed from config there is no problem
>>>
>>>> It seems rather benign though.
>>>>
>>> Well I wouldn't agree from power managment standpoint :). This nic is
>>> in a lot of laptops.
>>> 8% of 2.13GHz Core2Duo CPU is a lot :)
>>>
>>> Btw. should LKML be removed from cc?
>>> If you need any more help please ask.
>>> I hope I'm not harrasing you too much :)
>>>> --
>>>> Ueimor
>>>>
>>> Have a nice day
>>> Dushan
>>>
>> ...
>>
> Have a nice day
> Dushan
>

Re: ksoftirqd high cpu load on kernels 2.6.24 to 2.6.27-rc1-mm1

[Stephen Hemminger]

On Sun, 31 Aug 2008 10:51:46 +0200
"Dushan Tcholich" <dusanc@gmail.com> wrote:

> Hello
> I found the culprit.
> 
> When using powertop I get:
> Top causes for wakeups:
>   35,2% (251,0)                ip : br_stp_enable_bridge (br_hello_timer_expired
> 
> So I tried to turn them off with:
> brctl sethello br0 0
> but the problem persisted.


You can't turn off the hello timer, it is needed for Spanning Tree to
work. The kernel should reject requests to set hello timer < 1sec.
Most routers allow 1 - 10sec.

I am going to do a new patch to add tighter range checking for STP timer
settings and another to default fowarding delay of zero if STP is disabled.

[Bridge] [RFC] bridge: STP timer management range checking

[Stephen Hemminger]

The Spanning Tree Protocol timers need to be set within certain boundaries
to keep the internal protocol engine working, and to be interoperable.
This patch restricts changes to those timers to the values defined in IEEE 802.1D
specification.

The only exception to the standards are:
  * if STP is disabled allow forwarding delay to be turned off
  * allow wider range of ageing timer since this isn't directly part of
    STP, and setting it to zero allows for non-remembering bridge.

Warning: this may cause user backlash since apparently working but standards
  conforming configurations will get configuration errors that they didn't
  see before.

--- a/net/bridge/br_ioctl.c	2008-08-31 10:00:44.000000000 -0700
+++ b/net/bridge/br_ioctl.c	2008-08-31 10:34:00.000000000 -0700
@@ -177,38 +177,63 @@ static int old_dev_ioctl(struct net_devi
 	}
 
 	case BRCTL_SET_BRIDGE_FORWARD_DELAY:
+	{
+		unsigned long t = clock_t_to_jiffies(args[1]);
 		if (!capable(CAP_NET_ADMIN))
 			return -EPERM;
 
+		/* enforce range checking per IEEE 802.1D 17.14 */
+		if (br->stp_enabled != BR_NO_STP &&
+		    (t < 4*HZ || t > 30 * HZ))
+			return -EINVAL;
+
 		spin_lock_bh(&br->lock);
-		br->bridge_forward_delay = clock_t_to_jiffies(args[1]);
+		br->bridge_forward_delay = t;
 		if (br_is_root_bridge(br))
 			br->forward_delay = br->bridge_forward_delay;
 		spin_unlock_bh(&br->lock);
 		return 0;
-
+	}
 	case BRCTL_SET_BRIDGE_HELLO_TIME:
+	{
+		unsigned long t = clock_t_to_jiffies(args[1]);
+
 		if (!capable(CAP_NET_ADMIN))
 			return -EPERM;
 
+		if (t < HZ || t > 15 * HZ)
+			return -EINVAL;
+
 		spin_lock_bh(&br->lock);
-		br->bridge_hello_time = clock_t_to_jiffies(args[1]);
+		br->bridge_hello_time = t;
 		if (br_is_root_bridge(br))
 			br->hello_time = br->bridge_hello_time;
 		spin_unlock_bh(&br->lock);
 		return 0;
-
+	}
 	case BRCTL_SET_BRIDGE_MAX_AGE:
+	{
+		unsigned long t = clock_t_to_jiffies(args[1]);
 		if (!capable(CAP_NET_ADMIN))
 			return -EPERM;
 
+		/* enforce range checking per IEEE 802.1D 17.14 */
+		if (t < 6 * HZ || t > 40 * HZ)
+			return -EINVAL;
+
+		if (t < 2 * (br->bridge_hello_time + HZ))
+			return -EINVAL;
+
+		if (t / 2 + HZ > br->bridge_forward_delay)
+			return -EINVAL;
+
 		spin_lock_bh(&br->lock);
 		br->bridge_max_age = clock_t_to_jiffies(args[1]);
 		if (br_is_root_bridge(br))
 			br->max_age = br->bridge_max_age;
 		spin_unlock_bh(&br->lock);
 		return 0;
-
+	}
 	case BRCTL_SET_AGEING_TIME:
 		if (!capable(CAP_NET_ADMIN))
 			return -EPERM;
--- a/net/bridge/br_sysfs_br.c	2008-08-31 10:23:59.000000000 -0700
+++ b/net/bridge/br_sysfs_br.c	2008-08-31 10:32:53.000000000 -0700
@@ -29,11 +29,12 @@
  */
 static ssize_t store_bridge_parm(struct device *d,
 				 const char *buf, size_t len,
-				 void (*set)(struct net_bridge *, unsigned long))
+				 int (*set)(struct net_bridge *, unsigned long))
 {
 	struct net_bridge *br = to_bridge(d);
 	char *endp;
 	unsigned long val;
+	int rc;
 
 	if (!capable(CAP_NET_ADMIN))
 		return -EPERM;
@@ -43,9 +44,10 @@ static ssize_t store_bridge_parm(struct 
 		return -EINVAL;
 
 	spin_lock_bh(&br->lock);
-	(*set)(br, val);
+	rc = (*set)(br, val);
 	spin_unlock_bh(&br->lock);
-	return len;
+
+	return rc ? rc : len;
 }
 
 
@@ -56,12 +58,19 @@ static ssize_t show_forward_delay(struct
 	return sprintf(buf, "%lu\n", jiffies_to_clock_t(br->forward_delay));
 }
 
-static void set_forward_delay(struct net_bridge *br, unsigned long val)
+static int set_forward_delay(struct net_bridge *br, unsigned long val)
 {
 	unsigned long delay = clock_t_to_jiffies(val);
+
+	if (br->stp_enabled != BR_NO_STP &&
+	    (delay < 4*HZ || delay > 30 * HZ))
+		return -EINVAL;
+
 	br->forward_delay = delay;
 	if (br_is_root_bridge(br))
 		br->bridge_forward_delay = delay;
+
+	return 0;
 }
 
 static ssize_t store_forward_delay(struct device *d,
@@ -80,12 +89,18 @@ static ssize_t show_hello_time(struct de
 		       jiffies_to_clock_t(to_bridge(d)->hello_time));
 }
 
-static void set_hello_time(struct net_bridge *br, unsigned long val)
+static int set_hello_time(struct net_bridge *br, unsigned long val)
 {
 	unsigned long t = clock_t_to_jiffies(val);
+
+	if (t < HZ || t > 15 * HZ)
+		return -EINVAL;
+
 	br->hello_time = t;
 	if (br_is_root_bridge(br))
 		br->bridge_hello_time = t;
+
+	return 0;
 }
 
 static ssize_t store_hello_time(struct device *d,
@@ -104,12 +119,24 @@ static ssize_t show_max_age(struct devic
 		       jiffies_to_clock_t(to_bridge(d)->max_age));
 }
 
-static void set_max_age(struct net_bridge *br, unsigned long val)
+static int set_max_age(struct net_bridge *br, unsigned long val)
 {
 	unsigned long t = clock_t_to_jiffies(val);
+
+	/* enforce range checking per IEEE 802.1D 17.14 */
+	if (t < 6 * HZ || t > 40 * HZ)
+		return -EINVAL;
+
+	if (t < 2 * (br->bridge_hello_time + HZ))
+		return -EINVAL;
+
+	if (t / 2 + HZ > br->bridge_forward_delay)
+		return -EINVAL;
+
 	br->max_age = t;
 	if (br_is_root_bridge(br))
 		br->bridge_max_age = t;
+	return 0;
 }
 
 static ssize_t store_max_age(struct device *d, struct device_attribute *attr,
@@ -126,9 +153,10 @@ static ssize_t show_ageing_time(struct d
 	return sprintf(buf, "%lu\n", jiffies_to_clock_t(br->ageing_time));
 }
 
-static void set_ageing_time(struct net_bridge *br, unsigned long val)
+static int set_ageing_time(struct net_bridge *br, unsigned long val)
 {
 	br->ageing_time = clock_t_to_jiffies(val);
+	return 0;
 }
 
 static ssize_t store_ageing_time(struct device *d,
@@ -180,9 +208,10 @@ static ssize_t show_priority(struct devi
 		       (br->bridge_id.prio[0] << 8) | br->bridge_id.prio[1]);
 }
 
-static void set_priority(struct net_bridge *br, unsigned long val)
+static int set_priority(struct net_bridge *br, unsigned long val)
 {
 	br_stp_set_bridge_priority(br, (u16) val);
+	return 0;
 }
 
 static ssize_t store_priority(struct device *d, struct device_attribute *attr,

[RFC] bridge: STP timer management range checking

[Stephen Hemminger]

The Spanning Tree Protocol timers need to be set within certain boundaries
to keep the internal protocol engine working, and to be interoperable.
This patch restricts changes to those timers to the values defined in IEEE 802.1D
specification.

The only exception to the standards are:
  * if STP is disabled allow forwarding delay to be turned off
  * allow wider range of ageing timer since this isn't directly part of
    STP, and setting it to zero allows for non-remembering bridge.

Warning: this may cause user backlash since apparently working but standards
  conforming configurations will get configuration errors that they didn't
  see before.

--- a/net/bridge/br_ioctl.c	2008-08-31 10:00:44.000000000 -0700
+++ b/net/bridge/br_ioctl.c	2008-08-31 10:34:00.000000000 -0700
@@ -177,38 +177,63 @@ static int old_dev_ioctl(struct net_devi
 	}
 
 	case BRCTL_SET_BRIDGE_FORWARD_DELAY:
+	{
+		unsigned long t = clock_t_to_jiffies(args[1]);
 		if (!capable(CAP_NET_ADMIN))
 			return -EPERM;
 
+		/* enforce range checking per IEEE 802.1D 17.14 */
+		if (br->stp_enabled != BR_NO_STP &&
+		    (t < 4*HZ || t > 30 * HZ))
+			return -EINVAL;
+
 		spin_lock_bh(&br->lock);
-		br->bridge_forward_delay = clock_t_to_jiffies(args[1]);
+		br->bridge_forward_delay = t;
 		if (br_is_root_bridge(br))
 			br->forward_delay = br->bridge_forward_delay;
 		spin_unlock_bh(&br->lock);
 		return 0;
-
+	}
 	case BRCTL_SET_BRIDGE_HELLO_TIME:
+	{
+		unsigned long t = clock_t_to_jiffies(args[1]);
+
 		if (!capable(CAP_NET_ADMIN))
 			return -EPERM;
 
+		if (t < HZ || t > 15 * HZ)
+			return -EINVAL;
+
 		spin_lock_bh(&br->lock);
-		br->bridge_hello_time = clock_t_to_jiffies(args[1]);
+		br->bridge_hello_time = t;
 		if (br_is_root_bridge(br))
 			br->hello_time = br->bridge_hello_time;
 		spin_unlock_bh(&br->lock);
 		return 0;
-
+	}
 	case BRCTL_SET_BRIDGE_MAX_AGE:
+	{
+		unsigned long t = clock_t_to_jiffies(args[1]);
 		if (!capable(CAP_NET_ADMIN))
 			return -EPERM;
 
+		/* enforce range checking per IEEE 802.1D 17.14 */
+		if (t < 6 * HZ || t > 40 * HZ)
+			return -EINVAL;
+
+		if (t < 2 * (br->bridge_hello_time + HZ))
+			return -EINVAL;
+
+		if (t / 2 + HZ > br->bridge_forward_delay)
+			return -EINVAL;
+
 		spin_lock_bh(&br->lock);
 		br->bridge_max_age = clock_t_to_jiffies(args[1]);
 		if (br_is_root_bridge(br))
 			br->max_age = br->bridge_max_age;
 		spin_unlock_bh(&br->lock);
 		return 0;
-
+	}
 	case BRCTL_SET_AGEING_TIME:
 		if (!capable(CAP_NET_ADMIN))
 			return -EPERM;
--- a/net/bridge/br_sysfs_br.c	2008-08-31 10:23:59.000000000 -0700
+++ b/net/bridge/br_sysfs_br.c	2008-08-31 10:32:53.000000000 -0700
@@ -29,11 +29,12 @@
  */
 static ssize_t store_bridge_parm(struct device *d,
 				 const char *buf, size_t len,
-				 void (*set)(struct net_bridge *, unsigned long))
+				 int (*set)(struct net_bridge *, unsigned long))
 {
 	struct net_bridge *br = to_bridge(d);
 	char *endp;
 	unsigned long val;
+	int rc;
 
 	if (!capable(CAP_NET_ADMIN))
 		return -EPERM;
@@ -43,9 +44,10 @@ static ssize_t store_bridge_parm(struct 
 		return -EINVAL;
 
 	spin_lock_bh(&br->lock);
-	(*set)(br, val);
+	rc = (*set)(br, val);
 	spin_unlock_bh(&br->lock);
-	return len;
+
+	return rc ? rc : len;
 }
 
 
@@ -56,12 +58,19 @@ static ssize_t show_forward_delay(struct
 	return sprintf(buf, "%lu\n", jiffies_to_clock_t(br->forward_delay));
 }
 
-static void set_forward_delay(struct net_bridge *br, unsigned long val)
+static int set_forward_delay(struct net_bridge *br, unsigned long val)
 {
 	unsigned long delay = clock_t_to_jiffies(val);
+
+	if (br->stp_enabled != BR_NO_STP &&
+	    (delay < 4*HZ || delay > 30 * HZ))
+		return -EINVAL;
+
 	br->forward_delay = delay;
 	if (br_is_root_bridge(br))
 		br->bridge_forward_delay = delay;
+
+	return 0;
 }
 
 static ssize_t store_forward_delay(struct device *d,
@@ -80,12 +89,18 @@ static ssize_t show_hello_time(struct de
 		       jiffies_to_clock_t(to_bridge(d)->hello_time));
 }
 
-static void set_hello_time(struct net_bridge *br, unsigned long val)
+static int set_hello_time(struct net_bridge *br, unsigned long val)
 {
 	unsigned long t = clock_t_to_jiffies(val);
+
+	if (t < HZ || t > 15 * HZ)
+		return -EINVAL;
+
 	br->hello_time = t;
 	if (br_is_root_bridge(br))
 		br->bridge_hello_time = t;
+
+	return 0;
 }
 
 static ssize_t store_hello_time(struct device *d,
@@ -104,12 +119,24 @@ static ssize_t show_max_age(struct devic
 		       jiffies_to_clock_t(to_bridge(d)->max_age));
 }
 
-static void set_max_age(struct net_bridge *br, unsigned long val)
+static int set_max_age(struct net_bridge *br, unsigned long val)
 {
 	unsigned long t = clock_t_to_jiffies(val);
+
+	/* enforce range checking per IEEE 802.1D 17.14 */
+	if (t < 6 * HZ || t > 40 * HZ)
+		return -EINVAL;
+
+	if (t < 2 * (br->bridge_hello_time + HZ))
+		return -EINVAL;
+
+	if (t / 2 + HZ > br->bridge_forward_delay)
+		return -EINVAL;
+
 	br->max_age = t;
 	if (br_is_root_bridge(br))
 		br->bridge_max_age = t;
+	return 0;
 }
 
 static ssize_t store_max_age(struct device *d, struct device_attribute *attr,
@@ -126,9 +153,10 @@ static ssize_t show_ageing_time(struct d
 	return sprintf(buf, "%lu\n", jiffies_to_clock_t(br->ageing_time));
 }
 
-static void set_ageing_time(struct net_bridge *br, unsigned long val)
+static int set_ageing_time(struct net_bridge *br, unsigned long val)
 {
 	br->ageing_time = clock_t_to_jiffies(val);
+	return 0;
 }
 
 static ssize_t store_ageing_time(struct device *d,
@@ -180,9 +208,10 @@ static ssize_t show_priority(struct devi
 		       (br->bridge_id.prio[0] << 8) | br->bridge_id.prio[1]);
 }
 
-static void set_priority(struct net_bridge *br, unsigned long val)
+static int set_priority(struct net_bridge *br, unsigned long val)
 {
 	br_stp_set_bridge_priority(br, (u16) val);
+	return 0;
 }
 
 static ssize_t store_priority(struct device *d, struct device_attribute *attr,

Re: [Bridge] [RFC] bridge: STP timer management range checking

[Alan Cox]

On Sun, 31 Aug 2008 10:43:09 -0700
Stephen Hemminger <shemminger@vyatta.com> wrote:

> The Spanning Tree Protocol timers need to be set within certain boundaries
> to keep the internal protocol engine working, and to be interoperable.
> This patch restricts changes to those timers to the values defined in IEEE 802.1D
> specification.

Why do we care ? You have to be the network administrator to set values,
there are cases you may want to be out of the spec and you are
privileged. The kernel does need to stop things being done which are
fatal but running around restricting privileged administrators who have
the ability to bring the network down anyway isn't its job.

Seems bogus extra code to me - stops things working that should be
allowed too.

Re: [RFC] bridge: STP timer management range checking

[Alan Cox]

On Sun, 31 Aug 2008 10:43:09 -0700
Stephen Hemminger <shemminger@vyatta.com> wrote:

> The Spanning Tree Protocol timers need to be set within certain boundaries
> to keep the internal protocol engine working, and to be interoperable.
> This patch restricts changes to those timers to the values defined in IEEE 802.1D
> specification.

Why do we care ? You have to be the network administrator to set values,
there are cases you may want to be out of the spec and you are
privileged. The kernel does need to stop things being done which are
fatal but running around restricting privileged administrators who have
the ability to bring the network down anyway isn't its job.

Seems bogus extra code to me - stops things working that should be
allowed too.

Re: [Bridge] [RFC] bridge: STP timer management range checking

[Stephen Hemminger]

Alan Cox wrote:
> On Sun, 31 Aug 2008 10:43:09 -0700
> Stephen Hemminger <shemminger@vyatta.com> wrote:
>
>   
>> The Spanning Tree Protocol timers need to be set within certain boundaries
>> to keep the internal protocol engine working, and to be interoperable.
>> This patch restricts changes to those timers to the values defined in IEEE 802.1D
>> specification.
>>     
>
> Why do we care ? You have to be the network administrator to set values,
> there are cases you may want to be out of the spec and you are
> privileged. The kernel does need to stop things being done which are
> fatal but running around restricting privileged administrators who have
> the ability to bring the network down anyway isn't its job.
>
> Seems bogus extra code to me - stops things working that should be
> allowed too.
>   
The timer configuration is propagated in network protocol, so 
misconfigured Linux box
could survive but effect other devices on the network that are less 
robust. Maybe the
small values would cause some other bridge to crash, go infinite loop, ...
More likely robust devices might ignore our packets (because values out 
of range), leading to
routing loops and other disasters.

The kernel does need to stop administrative settings from taking out a 
network. If someone
has a custom device or other non-standard usage, they can always rebuild 
the kernel and
remove the range check.

Re: [RFC] bridge: STP timer management range checking

[Stephen Hemminger]

Alan Cox wrote:
> On Sun, 31 Aug 2008 10:43:09 -0700
> Stephen Hemminger <shemminger@vyatta.com> wrote:
>
>   
>> The Spanning Tree Protocol timers need to be set within certain boundaries
>> to keep the internal protocol engine working, and to be interoperable.
>> This patch restricts changes to those timers to the values defined in IEEE 802.1D
>> specification.
>>     
>
> Why do we care ? You have to be the network administrator to set values,
> there are cases you may want to be out of the spec and you are
> privileged. The kernel does need to stop things being done which are
> fatal but running around restricting privileged administrators who have
> the ability to bring the network down anyway isn't its job.
>
> Seems bogus extra code to me - stops things working that should be
> allowed too.
>   
The timer configuration is propagated in network protocol, so 
misconfigured Linux box
could survive but effect other devices on the network that are less 
robust. Maybe the
small values would cause some other bridge to crash, go infinite loop, ...
More likely robust devices might ignore our packets (because values out 
of range), leading to
routing loops and other disasters.

The kernel does need to stop administrative settings from taking out a 
network. If someone
has a custom device or other non-standard usage, they can always rebuild 
the kernel and
remove the range check.

Re: [Bridge] [RFC] bridge: STP timer management range checking

[Alan Cox]

> > Seems bogus extra code to me - stops things working that should be
> > allowed too.
> >   
> The timer configuration is propagated in network protocol, so 
> misconfigured Linux box
> could survive but effect other devices on the network that are less 
> robust. Maybe the

That would be irrelevant. CAP_NET_ADMIN lets you make that size mess
anyway.

> small values would cause some other bridge to crash, go infinite loop, ...
> More likely robust devices might ignore our packets (because values out 
> of range), leading to
> routing loops and other disasters.

Spamming tree isn't secure, news at 11.

> The kernel does need to stop administrative settings from taking out a 
> network. 

If you have CAP_NET_ADMIN you can trivially take out the network unless
it is properly switched.

Now you might want your pretty little GUI and/or config tools to warn
people that their configuration is outside 802 specs but that is a
different matter altogether

Alan

Re: [RFC] bridge: STP timer management range checking

[Alan Cox]

> > Seems bogus extra code to me - stops things working that should be
> > allowed too.
> >   
> The timer configuration is propagated in network protocol, so 
> misconfigured Linux box
> could survive but effect other devices on the network that are less 
> robust. Maybe the

That would be irrelevant. CAP_NET_ADMIN lets you make that size mess
anyway.

> small values would cause some other bridge to crash, go infinite loop, ...
> More likely robust devices might ignore our packets (because values out 
> of range), leading to
> routing loops and other disasters.

Spamming tree isn't secure, news at 11.

> The kernel does need to stop administrative settings from taking out a 
> network. 

If you have CAP_NET_ADMIN you can trivially take out the network unless
it is properly switched.

Now you might want your pretty little GUI and/or config tools to warn
people that their configuration is outside 802 specs but that is a
different matter altogether

Alan

Re: [Bridge] [RFC] bridge: STP timer management range checking

[Rick Jones]

Can one change the TCP maximum RTO to be smaller than specified in the 
specs?

rick jones

Re: [RFC] bridge: STP timer management range checking

[Rick Jones]

Can one change the TCP maximum RTO to be smaller than specified in the 
specs?

rick jones

Re: [Bridge] [RFC] bridge: STP timer management range checking

[David Miller]

From: Rick Jones <rick.jones2@hp.com>
Date: Tue, 02 Sep 2008 09:40:46 -0700

> Can one change the TCP maximum RTO to be smaller than specified in the specs?

We always min-clamp the RTO at RTO calculation time in order to be
compatible with BSD's coarse grained times.

Re: [RFC] bridge: STP timer management range checking

[David Miller]

From: Rick Jones <rick.jones2@hp.com>
Date: Tue, 02 Sep 2008 09:40:46 -0700

> Can one change the TCP maximum RTO to be smaller than specified in the specs?

We always min-clamp the RTO at RTO calculation time in order to be
compatible with BSD's coarse grained times.

Re: [Bridge] [RFC] bridge: STP timer management range checking

[Rick Jones]

David Miller wrote:
> From: Rick Jones <rick.jones2@hp.com>
> Date: Tue, 02 Sep 2008 09:40:46 -0700
>>Can one change the TCP maximum RTO to be smaller than specified in the specs? 
> We always min-clamp the RTO at RTO calculation time in order to be
> compatible with BSD's coarse grained times.

But tuning TCP_RTO_MAX isn't permitted right?  I'm drawing (perhaps 
flawed) parallels/distinctions between what is/isn't permitted to tweak 
for timers for one protocol versus another and wondering which may be a 
case of sauce for the goose/gander.

rick jones

Re: [RFC] bridge: STP timer management range checking

[Rick Jones]

David Miller wrote:
> From: Rick Jones <rick.jones2@hp.com>
> Date: Tue, 02 Sep 2008 09:40:46 -0700
>>Can one change the TCP maximum RTO to be smaller than specified in the specs? 
> We always min-clamp the RTO at RTO calculation time in order to be
> compatible with BSD's coarse grained times.

But tuning TCP_RTO_MAX isn't permitted right?  I'm drawing (perhaps 
flawed) parallels/distinctions between what is/isn't permitted to tweak 
for timers for one protocol versus another and wondering which may be a 
case of sauce for the goose/gander.

rick jones

Re: [Bridge] [RFC] bridge: STP timer management range checking

[Valdis.Kletnieks]

[-- Attachment #1: Type: text/plain, Size: 742 bytes --]

On Sun, 31 Aug 2008 10:43:09 PDT, Stephen Hemminger said:

> Warning: this may cause user backlash since apparently working but standards
>   conforming configurations will get configuration errors that they didn't
>   see before.

Did you mean "apparently working but *non*-standards conforming"?

Other than that, seems to be a sane application of "Be conservative in what you
send".  Our network is some 30K cat-5 ports, 1100 switches, 1300 wireless
access points, and we appreciate it every time somebody makes things more
bulletproof.  And yes, we prefer things to out-and-out *fail* rather than
run in a wonky configuration - hard failures usually get fixed in a few
minutes, wonkiness can drag on for months of mystifying symptoms...


[-- Attachment #2: Type: application/pgp-signature, Size: 226 bytes --]

Re: [RFC] bridge: STP timer management range checking

[Valdis.Kletnieks]

[-- Attachment #1: Type: text/plain, Size: 742 bytes --]

On Sun, 31 Aug 2008 10:43:09 PDT, Stephen Hemminger said:

> Warning: this may cause user backlash since apparently working but standards
>   conforming configurations will get configuration errors that they didn't
>   see before.

Did you mean "apparently working but *non*-standards conforming"?

Other than that, seems to be a sane application of "Be conservative in what you
send".  Our network is some 30K cat-5 ports, 1100 switches, 1300 wireless
access points, and we appreciate it every time somebody makes things more
bulletproof.  And yes, we prefer things to out-and-out *fail* rather than
run in a wonky configuration - hard failures usually get fixed in a few
minutes, wonkiness can drag on for months of mystifying symptoms...


[-- Attachment #2: Type: application/pgp-signature, Size: 226 bytes --]

Re: [Bridge] [RFC] bridge: STP timer management range checking

[David Miller]

From: Stephen Hemminger <shemminger@vyatta.com>
Date: Sun, 31 Aug 2008 10:43:09 -0700

> The Spanning Tree Protocol timers need to be set within certain boundaries
> to keep the internal protocol engine working, and to be interoperable.
> This patch restricts changes to those timers to the values defined in IEEE 802.1D
> specification.
> 
> The only exception to the standards are:
>   * if STP is disabled allow forwarding delay to be turned off
>   * allow wider range of ageing timer since this isn't directly part of
>     STP, and setting it to zero allows for non-remembering bridge.
> 
> Warning: this may cause user backlash since apparently working but standards
>   conforming configurations will get configuration errors that they didn't
>   see before.

I don't think we can really add these kinds of restrictions wholesale
like this.

And the user is reporting that using brctl to turn off STP doesn't
appear to actually turn off STP and thus fix all of the crazy
ksoftirqd high cpu load problems.

So what we need to do is resolve the user configuration issue that is
causing this problem to begin with.

Re: [RFC] bridge: STP timer management range checking

[David Miller]

From: Stephen Hemminger <shemminger@vyatta.com>
Date: Sun, 31 Aug 2008 10:43:09 -0700

> The Spanning Tree Protocol timers need to be set within certain boundaries
> to keep the internal protocol engine working, and to be interoperable.
> This patch restricts changes to those timers to the values defined in IEEE 802.1D
> specification.
> 
> The only exception to the standards are:
>   * if STP is disabled allow forwarding delay to be turned off
>   * allow wider range of ageing timer since this isn't directly part of
>     STP, and setting it to zero allows for non-remembering bridge.
> 
> Warning: this may cause user backlash since apparently working but standards
>   conforming configurations will get configuration errors that they didn't
>   see before.

I don't think we can really add these kinds of restrictions wholesale
like this.

And the user is reporting that using brctl to turn off STP doesn't
appear to actually turn off STP and thus fix all of the crazy
ksoftirqd high cpu load problems.

So what we need to do is resolve the user configuration issue that is
causing this problem to begin with.

[Bridge] [PATCH] bridge: don't allow setting hello time to zero

[Stephen Hemminger]

The bridge hello time can't be safely set to values less than 1 second,
otherwise it is possible to end up with a runaway timer.

Signed-off-by: Stephen Hemminger <shemminger@vyatta.com>

--- a/net/bridge/br_ioctl.c	2008-09-04 15:25:41.000000000 -0700
+++ b/net/bridge/br_ioctl.c	2008-09-04 15:44:33.000000000 -0700
@@ -188,15 +188,21 @@ static int old_dev_ioctl(struct net_devi
 		return 0;
 
 	case BRCTL_SET_BRIDGE_HELLO_TIME:
+	{
+		unsigned long t = clock_t_to_jiffies(args[1]);
 		if (!capable(CAP_NET_ADMIN))
 			return -EPERM;
 
+		if (t < HZ)
+			return -EINVAL;
+
 		spin_lock_bh(&br->lock);
-		br->bridge_hello_time = clock_t_to_jiffies(args[1]);
+		br->bridge_hello_time = t;
 		if (br_is_root_bridge(br))
 			br->hello_time = br->bridge_hello_time;
 		spin_unlock_bh(&br->lock);
 		return 0;
+	}
 
 	case BRCTL_SET_BRIDGE_MAX_AGE:
 		if (!capable(CAP_NET_ADMIN))
--- a/net/bridge/br_sysfs_br.c	2008-09-04 15:27:20.000000000 -0700
+++ b/net/bridge/br_sysfs_br.c	2008-09-04 15:33:31.000000000 -0700
@@ -29,11 +29,12 @@
  */
 static ssize_t store_bridge_parm(struct device *d,
 				 const char *buf, size_t len,
-				 void (*set)(struct net_bridge *, unsigned long))
+				 int (*set)(struct net_bridge *, unsigned long))
 {
 	struct net_bridge *br = to_bridge(d);
 	char *endp;
 	unsigned long val;
+	int err;
 
 	if (!capable(CAP_NET_ADMIN))
 		return -EPERM;
@@ -43,9 +44,9 @@ static ssize_t store_bridge_parm(struct 
 		return -EINVAL;
 
 	spin_lock_bh(&br->lock);
-	(*set)(br, val);
+	err = (*set)(br, val);
 	spin_unlock_bh(&br->lock);
-	return len;
+	return err ? err : len;
 }
 
 
@@ -56,12 +57,13 @@ static ssize_t show_forward_delay(struct
 	return sprintf(buf, "%lu\n", jiffies_to_clock_t(br->forward_delay));
 }
 
-static void set_forward_delay(struct net_bridge *br, unsigned long val)
+static int set_forward_delay(struct net_bridge *br, unsigned long val)
 {
 	unsigned long delay = clock_t_to_jiffies(val);
 	br->forward_delay = delay;
 	if (br_is_root_bridge(br))
 		br->bridge_forward_delay = delay;
+	return 0;
 }
 
 static ssize_t store_forward_delay(struct device *d,
@@ -80,12 +82,17 @@ static ssize_t show_hello_time(struct de
 		       jiffies_to_clock_t(to_bridge(d)->hello_time));
 }
 
-static void set_hello_time(struct net_bridge *br, unsigned long val)
+static int set_hello_time(struct net_bridge *br, unsigned long val)
 {
 	unsigned long t = clock_t_to_jiffies(val);
+
+	if (t < HZ)
+		return -EINVAL;
+
 	br->hello_time = t;
 	if (br_is_root_bridge(br))
 		br->bridge_hello_time = t;
+	return 0;
 }
 
 static ssize_t store_hello_time(struct device *d,
@@ -104,12 +111,13 @@ static ssize_t show_max_age(struct devic
 		       jiffies_to_clock_t(to_bridge(d)->max_age));
 }
 
-static void set_max_age(struct net_bridge *br, unsigned long val)
+static int set_max_age(struct net_bridge *br, unsigned long val)
 {
 	unsigned long t = clock_t_to_jiffies(val);
 	br->max_age = t;
 	if (br_is_root_bridge(br))
 		br->bridge_max_age = t;
+	return 0;
 }
 
 static ssize_t store_max_age(struct device *d, struct device_attribute *attr,
@@ -126,9 +134,10 @@ static ssize_t show_ageing_time(struct d
 	return sprintf(buf, "%lu\n", jiffies_to_clock_t(br->ageing_time));
 }
 
-static void set_ageing_time(struct net_bridge *br, unsigned long val)
+static int set_ageing_time(struct net_bridge *br, unsigned long val)
 {
 	br->ageing_time = clock_t_to_jiffies(val);
+	return 0;
 }
 
 static ssize_t store_ageing_time(struct device *d,
@@ -180,9 +189,10 @@ static ssize_t show_priority(struct devi
 		       (br->bridge_id.prio[0] << 8) | br->bridge_id.prio[1]);
 }
 
-static void set_priority(struct net_bridge *br, unsigned long val)
+static int set_priority(struct net_bridge *br, unsigned long val)
 {
 	br_stp_set_bridge_priority(br, (u16) val);
+	return 0;
 }
 
 static ssize_t store_priority(struct device *d, struct device_attribute *attr,

[PATCH] bridge: don't allow setting hello time to zero

[Stephen Hemminger]

The bridge hello time can't be safely set to values less than 1 second,
otherwise it is possible to end up with a runaway timer.

Signed-off-by: Stephen Hemminger <shemminger@vyatta.com>

--- a/net/bridge/br_ioctl.c	2008-09-04 15:25:41.000000000 -0700
+++ b/net/bridge/br_ioctl.c	2008-09-04 15:44:33.000000000 -0700
@@ -188,15 +188,21 @@ static int old_dev_ioctl(struct net_devi
 		return 0;
 
 	case BRCTL_SET_BRIDGE_HELLO_TIME:
+	{
+		unsigned long t = clock_t_to_jiffies(args[1]);
 		if (!capable(CAP_NET_ADMIN))
 			return -EPERM;
 
+		if (t < HZ)
+			return -EINVAL;
+
 		spin_lock_bh(&br->lock);
-		br->bridge_hello_time = clock_t_to_jiffies(args[1]);
+		br->bridge_hello_time = t;
 		if (br_is_root_bridge(br))
 			br->hello_time = br->bridge_hello_time;
 		spin_unlock_bh(&br->lock);
 		return 0;
+	}
 
 	case BRCTL_SET_BRIDGE_MAX_AGE:
 		if (!capable(CAP_NET_ADMIN))
--- a/net/bridge/br_sysfs_br.c	2008-09-04 15:27:20.000000000 -0700
+++ b/net/bridge/br_sysfs_br.c	2008-09-04 15:33:31.000000000 -0700
@@ -29,11 +29,12 @@
  */
 static ssize_t store_bridge_parm(struct device *d,
 				 const char *buf, size_t len,
-				 void (*set)(struct net_bridge *, unsigned long))
+				 int (*set)(struct net_bridge *, unsigned long))
 {
 	struct net_bridge *br = to_bridge(d);
 	char *endp;
 	unsigned long val;
+	int err;
 
 	if (!capable(CAP_NET_ADMIN))
 		return -EPERM;
@@ -43,9 +44,9 @@ static ssize_t store_bridge_parm(struct 
 		return -EINVAL;
 
 	spin_lock_bh(&br->lock);
-	(*set)(br, val);
+	err = (*set)(br, val);
 	spin_unlock_bh(&br->lock);
-	return len;
+	return err ? err : len;
 }
 
 
@@ -56,12 +57,13 @@ static ssize_t show_forward_delay(struct
 	return sprintf(buf, "%lu\n", jiffies_to_clock_t(br->forward_delay));
 }
 
-static void set_forward_delay(struct net_bridge *br, unsigned long val)
+static int set_forward_delay(struct net_bridge *br, unsigned long val)
 {
 	unsigned long delay = clock_t_to_jiffies(val);
 	br->forward_delay = delay;
 	if (br_is_root_bridge(br))
 		br->bridge_forward_delay = delay;
+	return 0;
 }
 
 static ssize_t store_forward_delay(struct device *d,
@@ -80,12 +82,17 @@ static ssize_t show_hello_time(struct de
 		       jiffies_to_clock_t(to_bridge(d)->hello_time));
 }
 
-static void set_hello_time(struct net_bridge *br, unsigned long val)
+static int set_hello_time(struct net_bridge *br, unsigned long val)
 {
 	unsigned long t = clock_t_to_jiffies(val);
+
+	if (t < HZ)
+		return -EINVAL;
+
 	br->hello_time = t;
 	if (br_is_root_bridge(br))
 		br->bridge_hello_time = t;
+	return 0;
 }
 
 static ssize_t store_hello_time(struct device *d,
@@ -104,12 +111,13 @@ static ssize_t show_max_age(struct devic
 		       jiffies_to_clock_t(to_bridge(d)->max_age));
 }
 
-static void set_max_age(struct net_bridge *br, unsigned long val)
+static int set_max_age(struct net_bridge *br, unsigned long val)
 {
 	unsigned long t = clock_t_to_jiffies(val);
 	br->max_age = t;
 	if (br_is_root_bridge(br))
 		br->bridge_max_age = t;
+	return 0;
 }
 
 static ssize_t store_max_age(struct device *d, struct device_attribute *attr,
@@ -126,9 +134,10 @@ static ssize_t show_ageing_time(struct d
 	return sprintf(buf, "%lu\n", jiffies_to_clock_t(br->ageing_time));
 }
 
-static void set_ageing_time(struct net_bridge *br, unsigned long val)
+static int set_ageing_time(struct net_bridge *br, unsigned long val)
 {
 	br->ageing_time = clock_t_to_jiffies(val);
+	return 0;
 }
 
 static ssize_t store_ageing_time(struct device *d,
@@ -180,9 +189,10 @@ static ssize_t show_priority(struct devi
 		       (br->bridge_id.prio[0] << 8) | br->bridge_id.prio[1]);
 }
 
-static void set_priority(struct net_bridge *br, unsigned long val)
+static int set_priority(struct net_bridge *br, unsigned long val)
 {
 	br_stp_set_bridge_priority(br, (u16) val);
+	return 0;
 }
 
 static ssize_t store_priority(struct device *d, struct device_attribute *attr,

Re: [Bridge] [PATCH] bridge: don't allow setting hello time to zero

[David Miller]

From: Stephen Hemminger <shemminger@vyatta.com>
Date: Thu, 4 Sep 2008 15:47:09 -0700

> The bridge hello time can't be safely set to values less than 1 second,
> otherwise it is possible to end up with a runaway timer.
> 
> Signed-off-by: Stephen Hemminger <shemminger@vyatta.com>

Applied, thanks Stephen.

I added more information to the commit message so that Dushan's
incredibly contribution to this bug getting fixed are mentioned.
I don't see how we would have figured out Bridging as even the
cause without his detective work.  So it's definitely wrong not
to give him at least some mention in the commit message :-/

bridge: don't allow setting hello time to zero

Dushan Tcholich reports that on his system ksoftirqd can consume
between %6 to %10 of cpu time, and cause ~200 context switches per
second.

He then correlated this with a report by bdupree@techfinesse.com:

	http://marc.info/?l=linux-kernel&m=119613299024398&w=2

and the culprit cause seems to be starting the bridge interface.
In particular, when starting the bridge interface, his scripts
are specifying a hello timer interval of "0".

The bridge hello time can't be safely set to values less than 1
second, otherwise it is possible to end up with a runaway timer.

Signed-off-by: Stephen Hemminger <shemminger@vyatta.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
---
 net/bridge/br_ioctl.c    |    8 +++++++-
 net/bridge/br_sysfs_br.c |   26 ++++++++++++++++++--------
 2 files changed, 25 insertions(+), 9 deletions(-)

diff --git a/net/bridge/br_ioctl.c b/net/bridge/br_ioctl.c
index eeee218..5bbf073 100644
--- a/net/bridge/br_ioctl.c
+++ b/net/bridge/br_ioctl.c
@@ -188,15 +188,21 @@ static int old_dev_ioctl(struct net_device *dev, struct ifreq *rq, int cmd)
 		return 0;
 
 	case BRCTL_SET_BRIDGE_HELLO_TIME:
+	{
+		unsigned long t = clock_t_to_jiffies(args[1]);
 		if (!capable(CAP_NET_ADMIN))
 			return -EPERM;
 
+		if (t < HZ)
+			return -EINVAL;
+
 		spin_lock_bh(&br->lock);
-		br->bridge_hello_time = clock_t_to_jiffies(args[1]);
+		br->bridge_hello_time = t;
 		if (br_is_root_bridge(br))
 			br->hello_time = br->bridge_hello_time;
 		spin_unlock_bh(&br->lock);
 		return 0;
+	}
 
 	case BRCTL_SET_BRIDGE_MAX_AGE:
 		if (!capable(CAP_NET_ADMIN))
diff --git a/net/bridge/br_sysfs_br.c b/net/bridge/br_sysfs_br.c
index 27d6a51..158dee8 100644
--- a/net/bridge/br_sysfs_br.c
+++ b/net/bridge/br_sysfs_br.c
@@ -29,11 +29,12 @@
  */
 static ssize_t store_bridge_parm(struct device *d,
 				 const char *buf, size_t len,
-				 void (*set)(struct net_bridge *, unsigned long))
+				 int (*set)(struct net_bridge *, unsigned long))
 {
 	struct net_bridge *br = to_bridge(d);
 	char *endp;
 	unsigned long val;
+	int err;
 
 	if (!capable(CAP_NET_ADMIN))
 		return -EPERM;
@@ -43,9 +44,9 @@ static ssize_t store_bridge_parm(struct device *d,
 		return -EINVAL;
 
 	spin_lock_bh(&br->lock);
-	(*set)(br, val);
+	err = (*set)(br, val);
 	spin_unlock_bh(&br->lock);
-	return len;
+	return err ? err : len;
 }
 
 
@@ -56,12 +57,13 @@ static ssize_t show_forward_delay(struct device *d,
 	return sprintf(buf, "%lu\n", jiffies_to_clock_t(br->forward_delay));
 }
 
-static void set_forward_delay(struct net_bridge *br, unsigned long val)
+static int set_forward_delay(struct net_bridge *br, unsigned long val)
 {
 	unsigned long delay = clock_t_to_jiffies(val);
 	br->forward_delay = delay;
 	if (br_is_root_bridge(br))
 		br->bridge_forward_delay = delay;
+	return 0;
 }
 
 static ssize_t store_forward_delay(struct device *d,
@@ -80,12 +82,17 @@ static ssize_t show_hello_time(struct device *d, struct device_attribute *attr,
 		       jiffies_to_clock_t(to_bridge(d)->hello_time));
 }
 
-static void set_hello_time(struct net_bridge *br, unsigned long val)
+static int set_hello_time(struct net_bridge *br, unsigned long val)
 {
 	unsigned long t = clock_t_to_jiffies(val);
+
+	if (t < HZ)
+		return -EINVAL;
+
 	br->hello_time = t;
 	if (br_is_root_bridge(br))
 		br->bridge_hello_time = t;
+	return 0;
 }
 
 static ssize_t store_hello_time(struct device *d,
@@ -104,12 +111,13 @@ static ssize_t show_max_age(struct device *d, struct device_attribute *attr,
 		       jiffies_to_clock_t(to_bridge(d)->max_age));
 }
 
-static void set_max_age(struct net_bridge *br, unsigned long val)
+static int set_max_age(struct net_bridge *br, unsigned long val)
 {
 	unsigned long t = clock_t_to_jiffies(val);
 	br->max_age = t;
 	if (br_is_root_bridge(br))
 		br->bridge_max_age = t;
+	return 0;
 }
 
 static ssize_t store_max_age(struct device *d, struct device_attribute *attr,
@@ -126,9 +134,10 @@ static ssize_t show_ageing_time(struct device *d,
 	return sprintf(buf, "%lu\n", jiffies_to_clock_t(br->ageing_time));
 }
 
-static void set_ageing_time(struct net_bridge *br, unsigned long val)
+static int set_ageing_time(struct net_bridge *br, unsigned long val)
 {
 	br->ageing_time = clock_t_to_jiffies(val);
+	return 0;
 }
 
 static ssize_t store_ageing_time(struct device *d,
@@ -180,9 +189,10 @@ static ssize_t show_priority(struct device *d, struct device_attribute *attr,
 		       (br->bridge_id.prio[0] << 8) | br->bridge_id.prio[1]);
 }
 
-static void set_priority(struct net_bridge *br, unsigned long val)
+static int set_priority(struct net_bridge *br, unsigned long val)
 {
 	br_stp_set_bridge_priority(br, (u16) val);
+	return 0;
 }
 
 static ssize_t store_priority(struct device *d, struct device_attribute *attr,
-- 
1.5.6.5.GIT

Re: [PATCH] bridge: don't allow setting hello time to zero

[David Miller]

From: Stephen Hemminger <shemminger@vyatta.com>
Date: Thu, 4 Sep 2008 15:47:09 -0700

> The bridge hello time can't be safely set to values less than 1 second,
> otherwise it is possible to end up with a runaway timer.
> 
> Signed-off-by: Stephen Hemminger <shemminger@vyatta.com>

Applied, thanks Stephen.

I added more information to the commit message so that Dushan's
incredibly contribution to this bug getting fixed are mentioned.
I don't see how we would have figured out Bridging as even the
cause without his detective work.  So it's definitely wrong not
to give him at least some mention in the commit message :-/

bridge: don't allow setting hello time to zero

Dushan Tcholich reports that on his system ksoftirqd can consume
between %6 to %10 of cpu time, and cause ~200 context switches per
second.

He then correlated this with a report by bdupree@techfinesse.com:

	http://marc.info/?l=linux-kernel&m=119613299024398&w=2

and the culprit cause seems to be starting the bridge interface.
In particular, when starting the bridge interface, his scripts
are specifying a hello timer interval of "0".

The bridge hello time can't be safely set to values less than 1
second, otherwise it is possible to end up with a runaway timer.

Signed-off-by: Stephen Hemminger <shemminger@vyatta.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
---
 net/bridge/br_ioctl.c    |    8 +++++++-
 net/bridge/br_sysfs_br.c |   26 ++++++++++++++++++--------
 2 files changed, 25 insertions(+), 9 deletions(-)

diff --git a/net/bridge/br_ioctl.c b/net/bridge/br_ioctl.c
index eeee218..5bbf073 100644
--- a/net/bridge/br_ioctl.c
+++ b/net/bridge/br_ioctl.c
@@ -188,15 +188,21 @@ static int old_dev_ioctl(struct net_device *dev, struct ifreq *rq, int cmd)
 		return 0;
 
 	case BRCTL_SET_BRIDGE_HELLO_TIME:
+	{
+		unsigned long t = clock_t_to_jiffies(args[1]);
 		if (!capable(CAP_NET_ADMIN))
 			return -EPERM;
 
+		if (t < HZ)
+			return -EINVAL;
+
 		spin_lock_bh(&br->lock);
-		br->bridge_hello_time = clock_t_to_jiffies(args[1]);
+		br->bridge_hello_time = t;
 		if (br_is_root_bridge(br))
 			br->hello_time = br->bridge_hello_time;
 		spin_unlock_bh(&br->lock);
 		return 0;
+	}
 
 	case BRCTL_SET_BRIDGE_MAX_AGE:
 		if (!capable(CAP_NET_ADMIN))
diff --git a/net/bridge/br_sysfs_br.c b/net/bridge/br_sysfs_br.c
index 27d6a51..158dee8 100644
--- a/net/bridge/br_sysfs_br.c
+++ b/net/bridge/br_sysfs_br.c
@@ -29,11 +29,12 @@
  */
 static ssize_t store_bridge_parm(struct device *d,
 				 const char *buf, size_t len,
-				 void (*set)(struct net_bridge *, unsigned long))
+				 int (*set)(struct net_bridge *, unsigned long))
 {
 	struct net_bridge *br = to_bridge(d);
 	char *endp;
 	unsigned long val;
+	int err;
 
 	if (!capable(CAP_NET_ADMIN))
 		return -EPERM;
@@ -43,9 +44,9 @@ static ssize_t store_bridge_parm(struct device *d,
 		return -EINVAL;
 
 	spin_lock_bh(&br->lock);
-	(*set)(br, val);
+	err = (*set)(br, val);
 	spin_unlock_bh(&br->lock);
-	return len;
+	return err ? err : len;
 }
 
 
@@ -56,12 +57,13 @@ static ssize_t show_forward_delay(struct device *d,
 	return sprintf(buf, "%lu\n", jiffies_to_clock_t(br->forward_delay));
 }
 
-static void set_forward_delay(struct net_bridge *br, unsigned long val)
+static int set_forward_delay(struct net_bridge *br, unsigned long val)
 {
 	unsigned long delay = clock_t_to_jiffies(val);
 	br->forward_delay = delay;
 	if (br_is_root_bridge(br))
 		br->bridge_forward_delay = delay;
+	return 0;
 }
 
 static ssize_t store_forward_delay(struct device *d,
@@ -80,12 +82,17 @@ static ssize_t show_hello_time(struct device *d, struct device_attribute *attr,
 		       jiffies_to_clock_t(to_bridge(d)->hello_time));
 }
 
-static void set_hello_time(struct net_bridge *br, unsigned long val)
+static int set_hello_time(struct net_bridge *br, unsigned long val)
 {
 	unsigned long t = clock_t_to_jiffies(val);
+
+	if (t < HZ)
+		return -EINVAL;
+
 	br->hello_time = t;
 	if (br_is_root_bridge(br))
 		br->bridge_hello_time = t;
+	return 0;
 }
 
 static ssize_t store_hello_time(struct device *d,
@@ -104,12 +111,13 @@ static ssize_t show_max_age(struct device *d, struct device_attribute *attr,
 		       jiffies_to_clock_t(to_bridge(d)->max_age));
 }
 
-static void set_max_age(struct net_bridge *br, unsigned long val)
+static int set_max_age(struct net_bridge *br, unsigned long val)
 {
 	unsigned long t = clock_t_to_jiffies(val);
 	br->max_age = t;
 	if (br_is_root_bridge(br))
 		br->bridge_max_age = t;
+	return 0;
 }
 
 static ssize_t store_max_age(struct device *d, struct device_attribute *attr,
@@ -126,9 +134,10 @@ static ssize_t show_ageing_time(struct device *d,
 	return sprintf(buf, "%lu\n", jiffies_to_clock_t(br->ageing_time));
 }
 
-static void set_ageing_time(struct net_bridge *br, unsigned long val)
+static int set_ageing_time(struct net_bridge *br, unsigned long val)
 {
 	br->ageing_time = clock_t_to_jiffies(val);
+	return 0;
 }
 
 static ssize_t store_ageing_time(struct device *d,
@@ -180,9 +189,10 @@ static ssize_t show_priority(struct device *d, struct device_attribute *attr,
 		       (br->bridge_id.prio[0] << 8) | br->bridge_id.prio[1]);
 }
 
-static void set_priority(struct net_bridge *br, unsigned long val)
+static int set_priority(struct net_bridge *br, unsigned long val)
 {
 	br_stp_set_bridge_priority(br, (u16) val);
+	return 0;
 }
 
 static ssize_t store_priority(struct device *d, struct device_attribute *attr,
-- 
1.5.6.5.GIT

Re: [Bridge] [PATCH] bridge: don't allow setting hello time to zero

[Dushan Tcholich]

On Mon, Sep 8, 2008 at 10:46 PM, David Miller <davem@davemloft.net> wrote:
> From: Stephen Hemminger <shemminger@vyatta.com>
> Date: Thu, 4 Sep 2008 15:47:09 -0700
>
>> The bridge hello time can't be safely set to values less than 1 second,
>> otherwise it is possible to end up with a runaway timer.
>>
>> Signed-off-by: Stephen Hemminger <shemminger@vyatta.com>
>
> Applied, thanks Stephen.
>
> I added more information to the commit message so that Dushan's
> incredibly contribution to this bug getting fixed are mentioned.
> I don't see how we would have figured out Bridging as even the
> cause without his detective work.  So it's definitely wrong not
> to give him at least some mention in the commit message :-/
>

I don't know what to say :)

Thank you
> bridge: don't allow setting hello time to zero
>
> Dushan Tcholich reports that on his system ksoftirqd can consume
> between %6 to %10 of cpu time, and cause ~200 context switches per
> second.
>
A little nitpick: 200 times greater context switch rate :), like
100000 per second.

> He then correlated this with a report by bdupree@techfinesse.com:
>
>        http://marc.info/?l=linux-kernel&m=119613299024398&w=2
>
> and the culprit cause seems to be starting the bridge interface.
> In particular, when starting the bridge interface, his scripts
> are specifying a hello timer interval of "0".
>
> The bridge hello time can't be safely set to values less than 1
> second, otherwise it is possible to end up with a runaway timer.

Btw. is there a way to make the command to turn STP off work too?
brctl stp br0 off
Because AFAIK if I shut down STP the hello timer should shut down too,
but it still continues to work.

Thank you for your time and effort

Dushan Tcholich

>
> Signed-off-by: Stephen Hemminger <shemminger@vyatta.com>
> Signed-off-by: David S. Miller <davem@davemloft.net>
> ---
>  net/bridge/br_ioctl.c    |    8 +++++++-
>  net/bridge/br_sysfs_br.c |   26 ++++++++++++++++++--------
>  2 files changed, 25 insertions(+), 9 deletions(-)
>
> diff --git a/net/bridge/br_ioctl.c b/net/bridge/br_ioctl.c
> index eeee218..5bbf073 100644
> --- a/net/bridge/br_ioctl.c
> +++ b/net/bridge/br_ioctl.c
> @@ -188,15 +188,21 @@ static int old_dev_ioctl(struct net_device *dev, struct ifreq *rq, int cmd)
>                return 0;
>
>        case BRCTL_SET_BRIDGE_HELLO_TIME:
> +       {
> +               unsigned long t = clock_t_to_jiffies(args[1]);
>                if (!capable(CAP_NET_ADMIN))
>                        return -EPERM;
>
> +               if (t < HZ)
> +                       return -EINVAL;
> +
>                spin_lock_bh(&br->lock);
> -               br->bridge_hello_time = clock_t_to_jiffies(args[1]);
> +               br->bridge_hello_time = t;
>                if (br_is_root_bridge(br))
>                        br->hello_time = br->bridge_hello_time;
>                spin_unlock_bh(&br->lock);
>                return 0;
> +       }
>
>        case BRCTL_SET_BRIDGE_MAX_AGE:
>                if (!capable(CAP_NET_ADMIN))
> diff --git a/net/bridge/br_sysfs_br.c b/net/bridge/br_sysfs_br.c
> index 27d6a51..158dee8 100644
> --- a/net/bridge/br_sysfs_br.c
> +++ b/net/bridge/br_sysfs_br.c
> @@ -29,11 +29,12 @@
>  */
>  static ssize_t store_bridge_parm(struct device *d,
>                                 const char *buf, size_t len,
> -                                void (*set)(struct net_bridge *, unsigned long))
> +                                int (*set)(struct net_bridge *, unsigned long))
>  {
>        struct net_bridge *br = to_bridge(d);
>        char *endp;
>        unsigned long val;
> +       int err;
>
>        if (!capable(CAP_NET_ADMIN))
>                return -EPERM;
> @@ -43,9 +44,9 @@ static ssize_t store_bridge_parm(struct device *d,
>                return -EINVAL;
>
>        spin_lock_bh(&br->lock);
> -       (*set)(br, val);
> +       err = (*set)(br, val);
>        spin_unlock_bh(&br->lock);
> -       return len;
> +       return err ? err : len;
>  }
>
>
> @@ -56,12 +57,13 @@ static ssize_t show_forward_delay(struct device *d,
>        return sprintf(buf, "%lu\n", jiffies_to_clock_t(br->forward_delay));
>  }
>
> -static void set_forward_delay(struct net_bridge *br, unsigned long val)
> +static int set_forward_delay(struct net_bridge *br, unsigned long val)
>  {
>        unsigned long delay = clock_t_to_jiffies(val);
>        br->forward_delay = delay;
>        if (br_is_root_bridge(br))
>                br->bridge_forward_delay = delay;
> +       return 0;
>  }
>
>  static ssize_t store_forward_delay(struct device *d,
> @@ -80,12 +82,17 @@ static ssize_t show_hello_time(struct device *d, struct device_attribute *attr,
>                       jiffies_to_clock_t(to_bridge(d)->hello_time));
>  }
>
> -static void set_hello_time(struct net_bridge *br, unsigned long val)
> +static int set_hello_time(struct net_bridge *br, unsigned long val)
>  {
>        unsigned long t = clock_t_to_jiffies(val);
> +
> +       if (t < HZ)
> +               return -EINVAL;
> +
>        br->hello_time = t;
>        if (br_is_root_bridge(br))
>                br->bridge_hello_time = t;
> +       return 0;
>  }
>
>  static ssize_t store_hello_time(struct device *d,
> @@ -104,12 +111,13 @@ static ssize_t show_max_age(struct device *d, struct device_attribute *attr,
>                       jiffies_to_clock_t(to_bridge(d)->max_age));
>  }
>
> -static void set_max_age(struct net_bridge *br, unsigned long val)
> +static int set_max_age(struct net_bridge *br, unsigned long val)
>  {
>        unsigned long t = clock_t_to_jiffies(val);
>        br->max_age = t;
>        if (br_is_root_bridge(br))
>                br->bridge_max_age = t;
> +       return 0;
>  }
>
>  static ssize_t store_max_age(struct device *d, struct device_attribute *attr,
> @@ -126,9 +134,10 @@ static ssize_t show_ageing_time(struct device *d,
>        return sprintf(buf, "%lu\n", jiffies_to_clock_t(br->ageing_time));
>  }
>
> -static void set_ageing_time(struct net_bridge *br, unsigned long val)
> +static int set_ageing_time(struct net_bridge *br, unsigned long val)
>  {
>        br->ageing_time = clock_t_to_jiffies(val);
> +       return 0;
>  }
>
>  static ssize_t store_ageing_time(struct device *d,
> @@ -180,9 +189,10 @@ static ssize_t show_priority(struct device *d, struct device_attribute *attr,
>                       (br->bridge_id.prio[0] << 8) | br->bridge_id.prio[1]);
>  }
>
> -static void set_priority(struct net_bridge *br, unsigned long val)
> +static int set_priority(struct net_bridge *br, unsigned long val)
>  {
>        br_stp_set_bridge_priority(br, (u16) val);
> +       return 0;
>  }
>
>  static ssize_t store_priority(struct device *d, struct device_attribute *attr,
> --
> 1.5.6.5.GIT
>
>

Re: [PATCH] bridge: don't allow setting hello time to zero

[Dushan Tcholich]

On Mon, Sep 8, 2008 at 10:46 PM, David Miller <davem@davemloft.net> wrote:
> From: Stephen Hemminger <shemminger@vyatta.com>
> Date: Thu, 4 Sep 2008 15:47:09 -0700
>
>> The bridge hello time can't be safely set to values less than 1 second,
>> otherwise it is possible to end up with a runaway timer.
>>
>> Signed-off-by: Stephen Hemminger <shemminger@vyatta.com>
>
> Applied, thanks Stephen.
>
> I added more information to the commit message so that Dushan's
> incredibly contribution to this bug getting fixed are mentioned.
> I don't see how we would have figured out Bridging as even the
> cause without his detective work.  So it's definitely wrong not
> to give him at least some mention in the commit message :-/
>

I don't know what to say :)

Thank you
> bridge: don't allow setting hello time to zero
>
> Dushan Tcholich reports that on his system ksoftirqd can consume
> between %6 to %10 of cpu time, and cause ~200 context switches per
> second.
>
A little nitpick: 200 times greater context switch rate :), like
100000 per second.

> He then correlated this with a report by bdupree@techfinesse.com:
>
>        http://marc.info/?l=linux-kernel&m=119613299024398&w=2
>
> and the culprit cause seems to be starting the bridge interface.
> In particular, when starting the bridge interface, his scripts
> are specifying a hello timer interval of "0".
>
> The bridge hello time can't be safely set to values less than 1
> second, otherwise it is possible to end up with a runaway timer.

Btw. is there a way to make the command to turn STP off work too?
brctl stp br0 off
Because AFAIK if I shut down STP the hello timer should shut down too,
but it still continues to work.

Thank you for your time and effort

Dushan Tcholich

>
> Signed-off-by: Stephen Hemminger <shemminger@vyatta.com>
> Signed-off-by: David S. Miller <davem@davemloft.net>
> ---
>  net/bridge/br_ioctl.c    |    8 +++++++-
>  net/bridge/br_sysfs_br.c |   26 ++++++++++++++++++--------
>  2 files changed, 25 insertions(+), 9 deletions(-)
>
> diff --git a/net/bridge/br_ioctl.c b/net/bridge/br_ioctl.c
> index eeee218..5bbf073 100644
> --- a/net/bridge/br_ioctl.c
> +++ b/net/bridge/br_ioctl.c
> @@ -188,15 +188,21 @@ static int old_dev_ioctl(struct net_device *dev, struct ifreq *rq, int cmd)
>                return 0;
>
>        case BRCTL_SET_BRIDGE_HELLO_TIME:
> +       {
> +               unsigned long t = clock_t_to_jiffies(args[1]);
>                if (!capable(CAP_NET_ADMIN))
>                        return -EPERM;
>
> +               if (t < HZ)
> +                       return -EINVAL;
> +
>                spin_lock_bh(&br->lock);
> -               br->bridge_hello_time = clock_t_to_jiffies(args[1]);
> +               br->bridge_hello_time = t;
>                if (br_is_root_bridge(br))
>                        br->hello_time = br->bridge_hello_time;
>                spin_unlock_bh(&br->lock);
>                return 0;
> +       }
>
>        case BRCTL_SET_BRIDGE_MAX_AGE:
>                if (!capable(CAP_NET_ADMIN))
> diff --git a/net/bridge/br_sysfs_br.c b/net/bridge/br_sysfs_br.c
> index 27d6a51..158dee8 100644
> --- a/net/bridge/br_sysfs_br.c
> +++ b/net/bridge/br_sysfs_br.c
> @@ -29,11 +29,12 @@
>  */
>  static ssize_t store_bridge_parm(struct device *d,
>                                 const char *buf, size_t len,
> -                                void (*set)(struct net_bridge *, unsigned long))
> +                                int (*set)(struct net_bridge *, unsigned long))
>  {
>        struct net_bridge *br = to_bridge(d);
>        char *endp;
>        unsigned long val;
> +       int err;
>
>        if (!capable(CAP_NET_ADMIN))
>                return -EPERM;
> @@ -43,9 +44,9 @@ static ssize_t store_bridge_parm(struct device *d,
>                return -EINVAL;
>
>        spin_lock_bh(&br->lock);
> -       (*set)(br, val);
> +       err = (*set)(br, val);
>        spin_unlock_bh(&br->lock);
> -       return len;
> +       return err ? err : len;
>  }
>
>
> @@ -56,12 +57,13 @@ static ssize_t show_forward_delay(struct device *d,
>        return sprintf(buf, "%lu\n", jiffies_to_clock_t(br->forward_delay));
>  }
>
> -static void set_forward_delay(struct net_bridge *br, unsigned long val)
> +static int set_forward_delay(struct net_bridge *br, unsigned long val)
>  {
>        unsigned long delay = clock_t_to_jiffies(val);
>        br->forward_delay = delay;
>        if (br_is_root_bridge(br))
>                br->bridge_forward_delay = delay;
> +       return 0;
>  }
>
>  static ssize_t store_forward_delay(struct device *d,
> @@ -80,12 +82,17 @@ static ssize_t show_hello_time(struct device *d, struct device_attribute *attr,
>                       jiffies_to_clock_t(to_bridge(d)->hello_time));
>  }
>
> -static void set_hello_time(struct net_bridge *br, unsigned long val)
> +static int set_hello_time(struct net_bridge *br, unsigned long val)
>  {
>        unsigned long t = clock_t_to_jiffies(val);
> +
> +       if (t < HZ)
> +               return -EINVAL;
> +
>        br->hello_time = t;
>        if (br_is_root_bridge(br))
>                br->bridge_hello_time = t;
> +       return 0;
>  }
>
>  static ssize_t store_hello_time(struct device *d,
> @@ -104,12 +111,13 @@ static ssize_t show_max_age(struct device *d, struct device_attribute *attr,
>                       jiffies_to_clock_t(to_bridge(d)->max_age));
>  }
>
> -static void set_max_age(struct net_bridge *br, unsigned long val)
> +static int set_max_age(struct net_bridge *br, unsigned long val)
>  {
>        unsigned long t = clock_t_to_jiffies(val);
>        br->max_age = t;
>        if (br_is_root_bridge(br))
>                br->bridge_max_age = t;
> +       return 0;
>  }
>
>  static ssize_t store_max_age(struct device *d, struct device_attribute *attr,
> @@ -126,9 +134,10 @@ static ssize_t show_ageing_time(struct device *d,
>        return sprintf(buf, "%lu\n", jiffies_to_clock_t(br->ageing_time));
>  }
>
> -static void set_ageing_time(struct net_bridge *br, unsigned long val)
> +static int set_ageing_time(struct net_bridge *br, unsigned long val)
>  {
>        br->ageing_time = clock_t_to_jiffies(val);
> +       return 0;
>  }
>
>  static ssize_t store_ageing_time(struct device *d,
> @@ -180,9 +189,10 @@ static ssize_t show_priority(struct device *d, struct device_attribute *attr,
>                       (br->bridge_id.prio[0] << 8) | br->bridge_id.prio[1]);
>  }
>
> -static void set_priority(struct net_bridge *br, unsigned long val)
> +static int set_priority(struct net_bridge *br, unsigned long val)
>  {
>        br_stp_set_bridge_priority(br, (u16) val);
> +       return 0;
>  }
>
>  static ssize_t store_priority(struct device *d, struct device_attribute *attr,
> --
> 1.5.6.5.GIT
>
>

Re: [Bridge] [PATCH] bridge: don't allow setting hello time to zero

[Stephen Hemminger]

On Mon, 8 Sep 2008 23:35:19 +0200
"Dushan Tcholich" <dusanc@gmail.com> wrote:

> On Mon, Sep 8, 2008 at 10:46 PM, David Miller <davem@davemloft.net> wrote:
> > From: Stephen Hemminger <shemminger@vyatta.com>
> > Date: Thu, 4 Sep 2008 15:47:09 -0700
> >
> >> The bridge hello time can't be safely set to values less than 1 second,
> >> otherwise it is possible to end up with a runaway timer.
> >>
> >> Signed-off-by: Stephen Hemminger <shemminger@vyatta.com>
> >
> > Applied, thanks Stephen.
> >
> > I added more information to the commit message so that Dushan's
> > incredibly contribution to this bug getting fixed are mentioned.
> > I don't see how we would have figured out Bridging as even the
> > cause without his detective work.  So it's definitely wrong not
> > to give him at least some mention in the commit message :-/
> >
> 
> I don't know what to say :)
> 
> Thank you
> > bridge: don't allow setting hello time to zero
> >
> > Dushan Tcholich reports that on his system ksoftirqd can consume
> > between %6 to %10 of cpu time, and cause ~200 context switches per
> > second.
> >
> A little nitpick: 200 times greater context switch rate :), like
> 100000 per second.
> 
> > He then correlated this with a report by bdupree@techfinesse.com:
> >
> >        http://marc.info/?l=linux-kernel&m=119613299024398&w=2
> >
> > and the culprit cause seems to be starting the bridge interface.
> > In particular, when starting the bridge interface, his scripts
> > are specifying a hello timer interval of "0".
> >
> > The bridge hello time can't be safely set to values less than 1
> > second, otherwise it is possible to end up with a runaway timer.
> 
> Btw. is there a way to make the command to turn STP off work too?
> brctl stp br0 off
> Because AFAIK if I shut down STP the hello timer should shut down too,
> but it still continues to work.
> 
> Thank you for your time and effort
> 
> Dushan Tcholich
>

The basics:
* Hello timer is always enabled
* STP defaults to off unless you turn it on
* Turn STP on/off with brctl.

In the existing design, the hello timer always runs, even when STP
is not turned on. If STP is not enabled, the packet is just never
created.  Fixing it would not be hard (or gain much), but would have
to deal with complex lock ordering and timer problems, so it isn't
worth fixing for current releases.

Re: [PATCH] bridge: don't allow setting hello time to zero

[Stephen Hemminger]

On Mon, 8 Sep 2008 23:35:19 +0200
"Dushan Tcholich" <dusanc@gmail.com> wrote:

> On Mon, Sep 8, 2008 at 10:46 PM, David Miller <davem@davemloft.net> wrote:
> > From: Stephen Hemminger <shemminger@vyatta.com>
> > Date: Thu, 4 Sep 2008 15:47:09 -0700
> >
> >> The bridge hello time can't be safely set to values less than 1 second,
> >> otherwise it is possible to end up with a runaway timer.
> >>
> >> Signed-off-by: Stephen Hemminger <shemminger@vyatta.com>
> >
> > Applied, thanks Stephen.
> >
> > I added more information to the commit message so that Dushan's
> > incredibly contribution to this bug getting fixed are mentioned.
> > I don't see how we would have figured out Bridging as even the
> > cause without his detective work.  So it's definitely wrong not
> > to give him at least some mention in the commit message :-/
> >
> 
> I don't know what to say :)
> 
> Thank you
> > bridge: don't allow setting hello time to zero
> >
> > Dushan Tcholich reports that on his system ksoftirqd can consume
> > between %6 to %10 of cpu time, and cause ~200 context switches per
> > second.
> >
> A little nitpick: 200 times greater context switch rate :), like
> 100000 per second.
> 
> > He then correlated this with a report by bdupree@techfinesse.com:
> >
> >        http://marc.info/?l=linux-kernel&m=119613299024398&w=2
> >
> > and the culprit cause seems to be starting the bridge interface.
> > In particular, when starting the bridge interface, his scripts
> > are specifying a hello timer interval of "0".
> >
> > The bridge hello time can't be safely set to values less than 1
> > second, otherwise it is possible to end up with a runaway timer.
> 
> Btw. is there a way to make the command to turn STP off work too?
> brctl stp br0 off
> Because AFAIK if I shut down STP the hello timer should shut down too,
> but it still continues to work.
> 
> Thank you for your time and effort
> 
> Dushan Tcholich
>

The basics:
* Hello timer is always enabled
* STP defaults to off unless you turn it on
* Turn STP on/off with brctl.

In the existing design, the hello timer always runs, even when STP
is not turned on. If STP is not enabled, the packet is just never
created.  Fixing it would not be hard (or gain much), but would have
to deal with complex lock ordering and timer problems, so it isn't
worth fixing for current releases.

Re: ksoftirqd high cpu load on kernels 2.6.24 to 2.6.27-rc1-mm1

[Dushan Tcholich]

Hi

On Sun, Aug 31, 2008 at 7:05 PM, Stephen Hemminger
<shemminger@vyatta.com> wrote:
> On Sun, 31 Aug 2008 10:51:46 +0200
> "Dushan Tcholich" <dusanc@gmail.com> wrote:
>
>> Hello
>> I found the culprit.
>>
>> When using powertop I get:
>> Top causes for wakeups:
>>   35,2% (251,0)                ip : br_stp_enable_bridge (br_hello_timer_expired
>>
>> So I tried to turn them off with:
>> brctl sethello br0 0
>> but the problem persisted.
>
>
> You can't turn off the hello timer, it is needed for Spanning Tree to
> work. The kernel should reject requests to set hello timer < 1sec.
> Most routers allow 1 - 10sec.
>
> I am going to do a new patch to add tighter range checking for STP timer
> settings and another to default fowarding delay of zero if STP is disabled.
>
Well I try to turn stp off but it doesn't  want to :)
This is in my /etc/conf.d/net
brctl_br0=( "setfd 0" "sethello 10" "stp off" )
I had problems with sethello 0 so now I'm using 10.
Tried with
brctl stp br0 off
but still had same troubles.

Have a nice day
Dushan