Re: kvm very slow

[Matthew Kent <mkent-rTVjrLRGJfNWk0Htik3J/w@public.gmane.org>]

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On Wed, 2007-01-08 at 07:22 +0200, Ulrich Schreiner wrote:
> hi,
> 
> im using a 64 bit fedora7 system with a quad-core processor to host
> multiple virtual machines.
> 

literally the exact same setup here

> my current kernel is:
> 
> Linux testserver 2.6.22.1-27.fc7 #1 SMP Tue Jul 17 17:19:58 EDT 2007
> x86_64 x86_64 x86_64 GNU/Linux
> 
> (now there is a 2.6.22.1-33.fc7 to download, but i think it is not the
> point here).
> 

2.6.22.1-41.fc7 x86_64 host

> i installed
> 
>   kvm.x86_64: 31-1.fc8

kvm-33

> 
> because of a crash i reported as a bug with the older kvm module.
> 
> this system starts a F7 image with the following command:
> 
> /usr/bin/qemu-kvm 
>   -net nic,macadr=52.54.00.12.34.57 
>   -net tap,script=./ifup.py,ifname=tap0
>   -hda /var/qemu/vm_images/F7image.img 
>   -boot c: -m 512 -vnc :2 -k de
> 
> inside the image there is fedora 7, but a 32bit system.
> 

almost exact same as here except using 32 bit fedora rawhide
(development) guest running kernel 2.6.23-0.74.rc2.git1.fc8

> almost everything works (reboot hangs), but the system is extremely
> slow! the clock inside the system is extremely slow: every *virtual*
> second in the image is about two or more seconds in the *real* world.

and I'm having the exact same issue here. The hardware clock works fine
(least from the output of /proc/driver/rtc and hwclock) but the system
time quickly falls behind in the guest, approx 0.5 secs for every 1 real
second.

No combination of selecting different clocksources in the guest,
disabling CONFIG_NO_HZ, etc seemed to make any difference. And the fact
is my fc7 x86_64 install works just great so I doubt its the host.

What I did notice though was ACPI wasn't being enabled by default for
the 32bit kernel with the message

ACPI: no DMI BIOS year, acpi=force is required to enable ACPI

and that the acpi_pm clocksource the x86_64 guest picked by default,
which worked fine, was missing. eg:

2.6.23-0.74.rc2.git1.fc8 i686 default boot:

/sys/devices/system/clocksource/clocksource0/available_clocksource
pit jiffies tsc
/sys/devices/system/clocksource/clocksource0/current_clocksource
pit

2.6.23-0.74.rc2.git1.fc8 i686 with acpi=force:

/sys/devices/system/clocksource/clocksource0/available_clocksource
tsc acpi_pm pit jiffies
/sys/devices/system/clocksource/clocksource0/current_clocksource
tsc

and now everything seems great, hardware and system time seem 1:1
again. 

Attached is a diff of the dmesg from each boot.

As to why this is...
-- 
Matthew Kent <mkent-rTVjrLRGJfNWk0Htik3J/w@public.gmane.org>
http://magoazul.com

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--- dmesg.f7_32bit_default	2007-08-09 16:00:00.000000000 -0700
+++ dmesg.f7_32bit_forced_acpi	2007-08-09 15:59:55.000000000 -0700
@@ -34,21 +34,30 @@
 ACPI: FACS 1FFF00C0, 0040
 ACPI: APIC 1FFF0938, 0040 (r1 QEMU   QEMUAPIC        1 QEMU        1)
 ACPI: no DMI BIOS year, acpi=force is required to enable ACPI
-ACPI: Disabling ACPI support
+ACPI: acpi=force override
+ACPI: PM-Timer IO Port: 0xb008
+ACPI: Local APIC address 0xfee00000
+ACPI: LAPIC (acpi_id[0x00] lapic_id[0x00] enabled)
+Processor #0 6:2 APIC version 17
+ACPI: IOAPIC (id[0x01] address[0xfec00000] gsi_base[0])
+IOAPIC[0]: apic_id 1, version 17, address 0xfec00000, GSI 0-23
+ACPI: IRQ11 used by override.
+Enabling APIC mode:  Flat.  Using 1 I/O APICs
+Using ACPI (MADT) for SMP configuration information
 Allocating PCI resources starting at 30000000 (gap: 20000000:dffc0000)
 swsusp: Registered nosave memory region: 000000000009f000 - 00000000000a0000
 swsusp: Registered nosave memory region: 00000000000a0000 - 00000000000e8000
 swsusp: Registered nosave memory region: 00000000000e8000 - 0000000000100000
 Built 1 zonelists in Zone order.  Total pages: 129265
-Kernel command line: ro root=/dev/VolGroup00/LogVol00 console=tty0 console=ttyS0 debug
-Found and enabled local APIC!
+Kernel command line: ro root=/dev/VolGroup00/LogVol00 console=tty0 console=ttyS0 debug acpi=force
 mapped APIC to ffffb000 (fee00000)
+mapped IOAPIC to ffffa000 (fec00000)
 Enabling fast FPU save and restore... done.
 Enabling unmasked SIMD FPU exception support... done.
 Initializing CPU#0
 CPU 0 irqstacks, hard=c0817000 soft=c07f7000
 PID hash table entries: 2048 (order: 11, 8192 bytes)
-Detected 2400.636 MHz processor.
+Detected 2400.387 MHz processor.
 Console: colour VGA+ 80x25
 console [tty0] enabled
 console [ttyS0] enabled
@@ -75,7 +84,7 @@
       .text : 0xc0400000 - 0xc063074d   (2241 kB)
 Checking if this processor honours the WP bit even in supervisor mode... Ok.
 SLUB: Genslabs=22, HWalign=64, Order=0-1, MinObjects=4, CPUs=1, Nodes=1
-Calibrating delay using timer specific routine.. 9619.97 BogoMIPS (lpj=4809986)
+Calibrating delay using timer specific routine.. 9622.99 BogoMIPS (lpj=4811496)
 Security Framework v1.0.0 initialized
 SELinux:  Initializing.
 SELinux:  Starting in permissive mode
@@ -92,8 +101,13 @@
 Checking 'hlt' instruction... OK.
 SMP alternatives: switching to UP code
 Freeing SMP alternatives: 12k freed
+ACPI: Core revision 20070126
 CPU0: Intel QEMU Virtual CPU version 0.9.0 stepping 03
-SMP motherboard not detected.
+Total of 1 processors activated (9622.99 BogoMIPS).
+ENABLING IO-APIC IRQs
+..TIMER: vector=0x31 apic1=0 pin1=0 apic2=-1 pin2=-1
+APIC calibration not consistent with PM Timer: 199ms instead of 100ms
+APIC delta adjusted to PM-Timer: 6249985 (12499675)
 Brought up 1 CPUs
 sizeof(vma)=84 bytes
 sizeof(page)=56 bytes
@@ -106,25 +120,36 @@
 khelper used greatest stack depth: 3160 bytes left
 Booting paravirtualized kernel on bare hardware
 khelper used greatest stack depth: 3084 bytes left
-Time: 22:48:42  Date: 07/09/107
+Time: 22:55:44  Date: 07/09/107
 NET: Registered protocol family 16
+ACPI: bus type pci registered
 PCI: PCI BIOS revision 2.10 entry at 0xfa130, last bus=0
 PCI: Using configuration type 1
 Setting up standard PCI resources
-khelper used greatest stack depth: 2928 bytes left
-ACPI: Interpreter disabled.
-Linux Plug and Play Support v0.97 (c) Adam Belay
-pnp: PnP ACPI: disabled
-usbcore: registered new interface driver usbfs
-usbcore: registered new interface driver hub
-usbcore: registered new device driver usb
-PCI: Probing PCI hardware
-PCI: Probing PCI hardware (bus 00)
+ACPI: Interpreter enabled
+ACPI: (supports)
+ACPI: Using IOAPIC for interrupt routing
+khelper used greatest stack depth: 2944 bytes left
+ACPI: PCI Root Bridge [PCI0] (0000:00)
 * Found PM-Timer Bug on the chipset. Due to workarounds for a bug,
 * this clock source is slow. Consider trying other clock sources
 PCI quirk: region b000-b03f claimed by PIIX4 ACPI
 PCI quirk: region b100-b10f claimed by PIIX4 SMB
-PCI: Using IRQ router PIIX/ICH [8086/7000] at 0000:00:01.0
+ACPI: PCI Interrupt Routing Table [\_SB_.PCI0._PRT]
+ACPI: PCI Interrupt Link [LNKA] (IRQs 3 4 5 6 7 9 10 *11 12)
+ACPI: PCI Interrupt Link [LNKB] (IRQs 3 4 5 6 7 *9 10 11 12)
+ACPI: PCI Interrupt Link [LNKC] (IRQs 3 4 5 6 7 9 10 *11 12)
+ACPI: PCI Interrupt Link [LNKD] (IRQs 3 4 5 6 7 *9 10 11 12)
+Linux Plug and Play Support v0.97 (c) Adam Belay
+pnp: PnP ACPI init
+ACPI: bus type pnp registered
+pnp: PnP ACPI: found 6 devices
+ACPI: ACPI bus type pnp unregistered
+usbcore: registered new interface driver usbfs
+usbcore: registered new interface driver hub
+usbcore: registered new device driver usb
+PCI: Using ACPI for IRQ routing
+PCI: If a device doesn't work, try "pci=routeirq".  If it helps, post a report
 NetLabel: Initializing
 NetLabel:  domain hash size = 128
 NetLabel:  protocols = UNLABELED CIPSOv4
@@ -139,10 +164,10 @@
 checking if image is initramfs... it is
 Freeing initrd memory: 3801k freed
 apm: BIOS version 1.2 Flags 0x03 (Driver version 1.16ac)
+apm: overridden by ACPI.
 audit: initializing netlink socket (disabled)
-audit(1186699721.596:1): initialized
+audit(1186700143.557:1): initialized
 Total HugeTLB memory allocated, 0
-khelper used greatest stack depth: 2888 bytes left
 VFS: Disk quotas dquot_6.5.1
 Dquot-cache hash table entries: 1024 (order 0, 4096 bytes)
 SELinux:  Registering netfilter hooks
@@ -159,17 +184,19 @@
 Activating ISA DMA hang workarounds.
 Boot video device is 0000:00:02.0
 pci_hotplug: PCI Hot Plug PCI Core version: 0.5
-khelper used greatest stack depth: 2860 bytes left
 isapnp: Scanning for PnP cards...
+Switched to high resolution mode on CPU 0
 isapnp: No Plug & Play device found
 Generic RTC Driver v1.07
 Non-volatile memory driver v1.2
 Linux agpgart interface v0.102
 Serial: 8250/16550 driver $Revision: 1.90 $ 4 ports, IRQ sharing enabled
 serial8250: ttyS0 at I/O 0x3f8 (irq = 4) is a 16450
+00:05: ttyS0 at I/O 0x3f8 (irq = 4) is a 16450
 RAMDISK driver initialized: 16 RAM disks of 16384K size 4096 blocksize
+khelper used greatest stack depth: 2784 bytes left
 input: Macintosh mouse button emulation as /class/input/input0
-PNP: No PS/2 controller found. Probing ports directly.
+PNP: PS/2 Controller [PNP0303:KBD,PNP0f13:MOU] at 0x60,0x64 irq 1,12
 serio: i8042 KBD port at 0x60,0x64 irq 1
 serio: i8042 AUX port at 0x60,0x64 irq 12
 mice: PS/2 mouse device common for all mice
@@ -182,17 +209,15 @@
 NET: Registered protocol family 1
 NET: Registered protocol family 17
 Using IPI No-Shortcut mode
-  Magic number: 3:809:855
+  Magic number: 3:912:956
 drivers/rtc/hctosys.c: unable to open rtc device (rtc0)
 Freeing unused kernel memory: 568k freed
 Write protecting the kernel read-only data: 916k
-Clocksource tsc unstable (delta = 542506452 ns)
-Time: pit clocksource has been installed.
+input: ImExPS/2 Generic Explorer Mouse as /class/input/input2
 USB Universal Host Controller Interface driver v3.0
-insmod used greatest stack depth: 2492 bytes left
+insmod used greatest stack depth: 2340 bytes left
 ohci_hcd: 2006 August 04 USB 1.1 'Open' Host Controller (OHCI) Driver
-insmod used greatest stack depth: 2400 bytes left
-input: ImExPS/2 Generic Explorer Mouse as /class/input/input2
+insmod used greatest stack depth: 2312 bytes left
 SCSI subsystem initialized
 libata version 2.21 loaded.
 ata_piix 0000:00:01.1: version 2.11
@@ -220,28 +245,25 @@
 scsi 1:0:0:0: CD-ROM            QEMU     QEMU CD-ROM      0.9. PQ: 0 ANSI: 5
 insmod used greatest stack depth: 876 bytes left
 device-mapper: ioctl: 4.11.0-ioctl (2006-10-12) initialised: dm-devel-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org
-EXT3-fs: INFO: recovery required on readonly filesystem.
-EXT3-fs: write access will be enabled during recovery.
 kjournald starting.  Commit interval 5 seconds
-EXT3-fs: dm-0: orphan cleanup on readonly fs
-ext3_orphan_cleanup: deleting unreferenced inode 2254377
-EXT3-fs: dm-0: 1 orphan inode deleted
-EXT3-fs: recovery complete.
 EXT3-fs: mounted filesystem with ordered data mode.
 SELinux:  Disabled at runtime.
 SELinux:  Unregistering netfilter hooks
-audit(1186699726.899:2): selinux=0 auid=4294967295
+audit(1186700148.939:2): selinux=0 auid=4294967295
 sd 0:0:0:0: Attached scsi generic sg0 type 0
 scsi 1:0:0:0: Attached scsi generic sg1 type 5
 sr0: scsi3-mmc drive: 4x/4x xa/form2 tray
 Uniform CD-ROM driver Revision: 3.20
 sr 1:0:0:0: Attached scsi CD-ROM sr0
-ne2k-pci.c:v1.03 9/22/2003 D. Becker/P. Gortmaker
-PCI: setting IRQ 11 as level-triggered
-PCI: Found IRQ 11 for device 0000:00:03.0
-eth0: RealTek RTL-8029 found at 0xc100, IRQ 11, 52:54:00:12:34:56.
 piix4_smbus 0000:00:01.3: Found 0000:00:01.3 device
+ne2k-pci.c:v1.03 9/22/2003 D. Becker/P. Gortmaker
+ACPI: PCI Interrupt Link [LNKC] enabled at IRQ 10
+ACPI: PCI Interrupt 0000:00:03.0[A] -> Link [LNKC] -> GSI 10 (level, low) -> IRQ 10
+eth0: RealTek RTL-8029 found at 0xc100, IRQ 10, 52:54:00:12:34:56.
+parport_pc 00:04: reported by Plug and Play ACPI
+parport0: PC-style at 0x378, irq 7 [PCSPP,EPP]
 FDC 0 is a S82078B
+No dock devices found.
 device-mapper: multipath: version 1.0.5 loaded
 EXT3 FS on dm-0, internal journal
 kjournald starting.  Commit interval 5 seconds

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