Re: poor sata performance on 2.6

[Prakash K. Cheemplavam]

Konstantin Sobolev wrote:
> On Thursday 15 April 2004 18:33, Justin Cormack wrote:
>
> > On Thu, 2004-04-15 at 15:26, Konstantin Sobolev wrote:
> >
> > > On Thursday 15 April 2004 18:00, Justin Cormack wrote:
> > >
> > > > hmm, odd. I get 50MB/s or so from normal (7200, 8MB cache) WD disks,
> > > > and Seagate from the same controller. Can you send lspci,
> > > > /proc/interrupts and dmesg...
> > >
> > > Attached are files for 2.6.5-mm5 with highmem, ACPI and APIC turned off.
> >
> > ah. Make a filesystem on it and mount it and try again. I see you have
> > no partition table and so probably no filesystem. This means the block
> > size is set to default 512byte not 4k which makes disk operations slow.
> > Any filesystem should default to block size of 4k, eg ext2.
>
>
> Very interesting!
> created partition table,
> kos sata # mkfs.ext2 /dev/sda1
> [..skipped..]
> kos mnt # cd /
> kos / # mkdir wd
> kos / # mount /dev/sda1 /wd
> kos / # hdparm -t -a8192 /dev/sda

[snip]

> So first time it gave the same loosy 27 MB/s and subsequent tests give pretty 
> good 68 MB/s! Why?

I once reported that to lkml but got no reaction. siimage.c doesn't show 
this behaviour.

Prakash
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