Re: poor sata performance on 2.6

Prakash K. Cheemplavam
2004-04-15T14:52:15Z

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