Re: 'Sloppier' PCI access checks in main tree

[Stijn De Weirdt <stijn.deweirdt@gmail.com>]

i give a snapshot of dmesg of a vm:
Uniform Multi-Platform E-IDE driver Revision: 7.00beta4-2.4
ide: Assuming 50MHz system bus speed for PIO modes; override with idebus=xx
hda: C/H/S=0/0/0 from BIOS ignored
hdb: C/H/S=0/0/0 from BIOS ignored

output of working system (dmesg from dom0 is very similar and works normal)
Uniform Multi-Platform E-IDE driver Revision: 7.00beta4-2.4
ide: Assuming 33MHz system bus speed for PIO modes; override with idebus=xx
ICH5: IDE controller at PCI slot 00:1f.1
PCI: Enabling device 00:1f.1 (0005 -> 0007)
PCI: Found IRQ 10 for device 00:1f.1
PCI: Sharing IRQ 10 with 00:1d.2
PCI: Sharing IRQ 10 with 00:1f.2
ICH5: chipset revision 2
ICH5: not 100% native mode: will probe irqs later
    ide0: BM-DMA at 0xffa0-0xffa7, BIOS settings: hda:DMA, hdb:pio
    ide1: BM-DMA at 0xffa8-0xffaf, BIOS settings: hdc:DMA, hdd:pio
hda: Maxtor 6Y080L0, ATA DISK drive
blk: queue c043ea80, I/O limit 4095Mb (mask 0xffffffff)
hdc: SONY CD-RW CRX320E, ATAPI CD/DVD-ROM drive
ide0 at 0x1f0-0x1f7,0x3f6 on irq 14
ide1 at 0x170-0x177,0x376 on irq 15
hda: attached ide-disk driver.
hda: host protected area => 1
hda: 160086528 sectors (81964 MB) w/2048KiB Cache, CHS=158816/16/63, UDMA(100)
ide-floppy driver 0.99.newide
Partition check:
 /dev/ide/host0/bus0/target0/lun0: p1 p2 p3 p4 < p5 p6 p7 p8 >

so i think that the correct controller is found in dom0, but in a vm
(using same xen0-kernel)
performance is bad (about the network, transfer speeds are high, but a
ssh login takes about 40 sec)

stijn

On Wed, 12 Jan 2005 08:39:21 +0000, Ian Pratt <Ian.Pratt@cl.cam.ac.uk> wrote:
> > sorry missed this email.
> > i'm using 2.4.28. i'll try today, since i have to recompile my kernel
> > anyway.
> 
> OK, that explains a lot. We might back-port the vm86 and full
> /dev/mem support to 2.4, but its not high on the todo
> list. Perhaps a volunteer from the audience will step up at this
> point ? :-)
> 
> > reaction times on my system are anything but good (what
> > performace loss should i expect if i use a file-backed vbd (and what
> > fs is the most for those). also network seems pretty slow.
> 
> The performance loss using file-backed vbd's is typically pretty
> small, but I do generally use LVM volumes. Our systems manage to
> saturate gigabit Ethernet links no problem, so I'm surprised
> you're seeing network slow downs. There have been reports about
> IRQ problems causing slow downs on some systems, and we're
> investigating.
> 
> Ian
>


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