Re: [PATCH] libata: implement ata_qc_exec_internal()

[Tejun Heo <htejun@gmail.com>]

Raz Ben-Jehuda(caro) wrote:
> does it solve the cpu usage ?
> 
> On 11/28/05, Tejun Heo <htejun@gmail.com> wrote:
> 
>>Each user libata internal commands initializes a qc, issues it, waits
>>for its completion and checks for errors.  This patch factors internal
>>command execution sequence into ata_qc_exec_internal().  The function
>>also removes race condition between irq and timeout handling.
>>
>>Signed-off-by: Tejun Heo <htejun@gmail.com>
>>

Hi, Raz.

It propabably has nothing to do with the cpu usage problem on piix you 
reported.  I think you need to post more data to get people on the list 
interested in your problem.  The followings may help.

1. Please report exactly which kernel you're using and more information 
on the hardware will also help.

2. Don't use raid or any fs on it.  Just perform tests on raw /dev/sdx 
devices.  Do something like 'time dd if=/dev/sdx of=/dev/zero bs=1M 
count=1024' and report how much user/system time it uses.

3. If above shows large system time consumption, build your kernel with 
oprofile.  Start recording non-idle cpu cycles (the default) including 
the kernel.  Repeat test in #2.  Dump oprofile result and post that here.

Hope it helps.

-- 
tejun