----- Original Message ----
> From: Fengguang Wu <[email protected]>
> To: Martin Knoblauch <[email protected]>
> Cc: Mike Snitzer <[email protected]>; Peter Zijlstra <[email protected]>; [email protected]; Ingo Molnar <[email protected]>; [email protected]; "[email protected]" <[email protected]>; Linus Torvalds <[email protected]>
> Sent: Wednesday, January 16, 2008 1:00:04 PM
> Subject: Re: regression: 100% io-wait with 2.6.24-rcX
>
> On Wed, Jan 16, 2008 at 01:26:41AM -0800, Martin Knoblauch wrote:
> > > For those interested in using your writeback improvements in
> > > production sooner rather than later (primarily with ext3); what
> > > recommendations do you have? Just heavily test our own 2.6.24
> +
>
your
> > > evolving "close, but not ready for merge" -mm writeback patchset?
> > >
> > Hi Fengguang, Mike,
> >
> > I can add myself to Mikes question. It would be good to know
> a
>
"roadmap" for the writeback changes. Testing 2.6.24-rcX so far has
> been
>
showing quite nice improvement of the overall writeback situation and
> it
>
would be sad to see this [partially] gone in 2.6.24-final.
> Linus
>
apparently already has reverted "...2250b". I will definitely repeat my
> tests
>
with -rc8. and report.
>
> Thank you, Martin. Can you help test this patch on 2.6.24-rc7?
> Maybe we can push it to 2.6.24 after your testing.
>
Hi Fengguang,
something really bad has happened between -rc3 and -rc6. Embarrassingly I did not catch that earlier :-(
Compared to the numbers I posted in http://lkml.org/lkml/2007/10/26/208 , dd1 is now at 60 MB/sec (slight plus), while dd2/dd3 suck the same way as in pre 2.6.24. The only test that is still good is mix3, which I attribute to the per-BDI stuff.
At the moment I am frantically trying to find when things went down. I did run -rc8 and rc8+yourpatch. No difference to what I see with -rc6. Sorry that I cannot provide any input to your patch.
Depressed
Martin
On Jan 17, 2008 8:52 AM, Martin Knoblauch <[email protected]> wrote:
>
> ----- Original Message ----
> > From: Fengguang Wu <[email protected]>
> > To: Martin Knoblauch <[email protected]>
> > Cc: Mike Snitzer <[email protected]>; Peter Zijlstra <[email protected]>; [email protected]; Ingo Molnar <[email protected]>; [email protected]; "[email protected]" <[email protected]>; Linus Torvalds <[email protected]>
> > Sent: Wednesday, January 16, 2008 1:00:04 PM
> > Subject: Re: regression: 100% io-wait with 2.6.24-rcX
> >
> > On Wed, Jan 16, 2008 at 01:26:41AM -0800, Martin Knoblauch wrote:
> > > > For those interested in using your writeback improvements in
> > > > production sooner rather than later (primarily with ext3); what
> > > > recommendations do you have? Just heavily test our own 2.6.24
> > +
> >
> your
> > > > evolving "close, but not ready for merge" -mm writeback patchset?
> > > >
> > > Hi Fengguang, Mike,
> > >
> > > I can add myself to Mikes question. It would be good to know
> > a
> >
> "roadmap" for the writeback changes. Testing 2.6.24-rcX so far has
> > been
> >
> showing quite nice improvement of the overall writeback situation and
> > it
> >
> would be sad to see this [partially] gone in 2.6.24-final.
> > Linus
> >
> apparently already has reverted "...2250b". I will definitely repeat my
> > tests
> >
> with -rc8. and report.
> >
> > Thank you, Martin. Can you help test this patch on 2.6.24-rc7?
> > Maybe we can push it to 2.6.24 after your testing.
> >
> Hi Fengguang,
>
> something really bad has happened between -rc3 and -rc6. Embarrassingly I did not catch that earlier :-(
>
> Compared to the numbers I posted in http://lkml.org/lkml/2007/10/26/208 , dd1 is now at 60 MB/sec (slight plus), while dd2/dd3 suck the same way as in pre 2.6.24. The only test that is still good is mix3, which I attribute to the per-BDI stuff.
>
> At the moment I am frantically trying to find when things went down. I did run -rc8 and rc8+yourpatch. No difference to what I see with -rc6. Sorry that I cannot provide any input to your patch.
>
> Depressed
> Martin
Martin,
I've backported Peter's perbdi patchset to 2.6.22.x. I can share it
with anyone who might be interested.
As expected, it has yielded 2.6.24-rcX level scaling. Given the test
result matrix you previously posted, 2.6.22.x+perbdi might give you
what you're looking for (sans improved writeback that 2.6.24 was
thought to be providing). That is, much improved scaling with better
O_DIRECT and network throughput. Just a thought...
Unfortunately, my priorities (and computing resources) have shifted
and I won't be able to thoroughly test Fengguang's new writeback patch
on 2.6.24-rc8... whereby missing out on providing
justification/testing to others on _some_ improved writeback being
included in 2.6.24 final.
Not to mention the window for writeback improvement is all but closed
considering the 2.6.24-rc8 announcement's 2.6.24 final release
timetable.
regards,
Mike