* cfq-iosched: a regression
@ 2011-08-16 2:47 Shaohua Li
2011-08-18 20:22 ` Justin TerAvest
2011-08-19 6:33 ` Jens Axboe
0 siblings, 2 replies; 4+ messages in thread
From: Shaohua Li @ 2011-08-16 2:47 UTC (permalink / raw)
To: Jens Axboe; +Cc: teravest, lkml, Shi, Alex
We have a kernel build regression since 3.1-rc1, which is about 10%
regression. The kernel source is in an ext3 filesystem.
Alex Shi bisect it to commit:
commit a07405b7802691d29ab3b23bdc76ee6d006aad0b
Author: Justin TerAvest <teravest@google.com>
Date: Sun Jul 10 22:09:19 2011 +0200
cfq: Remove special treatment for metadata rqs.
Apparently this is caused by lack metadata preemption, where ext3/ext4
do use READ_META. I didn't see a way to fix the issue, so suggest
reverting the patch.
Reported-by: Alex Shi<alex.shi@intel.com>
Reported-by: Shaohua Li<shaohua.li@intel.com>
^ permalink raw reply [flat|nested] 4+ messages in thread* Re: cfq-iosched: a regression
2011-08-16 2:47 cfq-iosched: a regression Shaohua Li
@ 2011-08-18 20:22 ` Justin TerAvest
2011-08-19 0:21 ` Shaohua Li
2011-08-19 6:33 ` Jens Axboe
1 sibling, 1 reply; 4+ messages in thread
From: Justin TerAvest @ 2011-08-18 20:22 UTC (permalink / raw)
To: Shaohua Li; +Cc: Jens Axboe, lkml, Shi, Alex
Hi Shaohua,
What was the workload you were running to find this regression?
On Mon, Aug 15, 2011 at 7:47 PM, Shaohua Li <shaohua.li@intel.com> wrote:
> We have a kernel build regression since 3.1-rc1, which is about 10%
> regression. The kernel source is in an ext3 filesystem.
> Alex Shi bisect it to commit:
> commit a07405b7802691d29ab3b23bdc76ee6d006aad0b
> Author: Justin TerAvest <teravest@google.com>
> Date: Sun Jul 10 22:09:19 2011 +0200
>
> cfq: Remove special treatment for metadata rqs.
>
> Apparently this is caused by lack metadata preemption, where ext3/ext4
> do use READ_META. I didn't see a way to fix the issue, so suggest
> reverting the patch.
>
> Reported-by: Alex Shi<alex.shi@intel.com>
> Reported-by: Shaohua Li<shaohua.li@intel.com>
>
>
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: cfq-iosched: a regression
2011-08-18 20:22 ` Justin TerAvest
@ 2011-08-19 0:21 ` Shaohua Li
0 siblings, 0 replies; 4+ messages in thread
From: Shaohua Li @ 2011-08-19 0:21 UTC (permalink / raw)
To: Justin TerAvest; +Cc: Jens Axboe, lkml, Shi, Alex
On Fri, 2011-08-19 at 04:22 +0800, Justin TerAvest wrote:
> Hi Shaohua,
>
> What was the workload you were running to find this regression?
kernel build as I declared below.
Thanks,
Shaohua
> On Mon, Aug 15, 2011 at 7:47 PM, Shaohua Li <shaohua.li@intel.com> wrote:
> > We have a kernel build regression since 3.1-rc1, which is about 10%
> > regression. The kernel source is in an ext3 filesystem.
> > Alex Shi bisect it to commit:
> > commit a07405b7802691d29ab3b23bdc76ee6d006aad0b
> > Author: Justin TerAvest <teravest@google.com>
> > Date: Sun Jul 10 22:09:19 2011 +0200
> >
> > cfq: Remove special treatment for metadata rqs.
> >
> > Apparently this is caused by lack metadata preemption, where ext3/ext4
> > do use READ_META. I didn't see a way to fix the issue, so suggest
> > reverting the patch.
> >
> > Reported-by: Alex Shi<alex.shi@intel.com>
> > Reported-by: Shaohua Li<shaohua.li@intel.com>
> >
> >
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: cfq-iosched: a regression
2011-08-16 2:47 cfq-iosched: a regression Shaohua Li
2011-08-18 20:22 ` Justin TerAvest
@ 2011-08-19 6:33 ` Jens Axboe
1 sibling, 0 replies; 4+ messages in thread
From: Jens Axboe @ 2011-08-19 6:33 UTC (permalink / raw)
To: Shaohua Li; +Cc: teravest@google.com, lkml, Shi, Alex
On 2011-08-16 04:47, Shaohua Li wrote:
> We have a kernel build regression since 3.1-rc1, which is about 10%
> regression. The kernel source is in an ext3 filesystem.
> Alex Shi bisect it to commit:
> commit a07405b7802691d29ab3b23bdc76ee6d006aad0b
> Author: Justin TerAvest <teravest@google.com>
> Date: Sun Jul 10 22:09:19 2011 +0200
>
> cfq: Remove special treatment for metadata rqs.
>
> Apparently this is caused by lack metadata preemption, where ext3/ext4
> do use READ_META. I didn't see a way to fix the issue, so suggest
> reverting the patch.
>
> Reported-by: Alex Shi<alex.shi@intel.com>
> Reported-by: Shaohua Li<shaohua.li@intel.com>
I had a gut feeling on that meta data, it's hard to know exactly where
it helps at this point. I'll revert the commit and then we can diagnose
this on the side.
--
Jens Axboe
^ permalink raw reply [flat|nested] 4+ messages in thread
end of thread, other threads:[~2011-08-19 6:34 UTC | newest]
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2011-08-16 2:47 cfq-iosched: a regression Shaohua Li
2011-08-18 20:22 ` Justin TerAvest
2011-08-19 0:21 ` Shaohua Li
2011-08-19 6:33 ` Jens Axboe
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