Re: [performance bug] kernel building regression on 64 LCPUsmachine

From: Jan Kara
Date: Wed Mar 02 2011 - 04:42:53 EST


On Tue 01-03-11 14:56:43, Jeff Moyer wrote:
> Corrado Zoccolo <czoccolo@xxxxxxxxx> writes:
>
> > On Thu, Feb 24, 2011 at 1:13 PM, Jan Kara <jack@xxxxxxx> wrote:
> >> On Wed 23-02-11 16:24:47, Alex,Shi wrote:
> >>> Though these patches can not totally recovered the problem, but they are
> >>> quite helpful with ccache enabled situation. It increase 10% performance
> >>> on 38-rc1 kernel.
> >>  OK and what was the original performance drop with WRITE_SYNC change?
> >>
> >>> I have tried to enabled they to latest rc6 kernel but failed. the vmstat output is here:
> >>> with patches:
> >>  I'm attaching patches rebased on top of latest Linus's tree.
> >> Corrado, could you possibly run your fsync-heavy tests so that we see
> >> whether there isn't negative impact of my patches on your fsync-heavy
> >> workload? Thanks.
> > The workload was actually Jeff's, and the stalls that my change tried
> > to mitigate showed up on his enterprise class storage. Adding him so
> > he can test it.
>
> Sorry for the late reply. You can use either fs_mark or iozone to
> generate an fsync-heavy workload. The test I did was to mix this with a
> sequential reader. If you can point me at patches, I should be able to
> test this.
The latest version of patches is attached to:
https://lkml.org/lkml/2011/2/24/125

Honza
--
Jan Kara <jack@xxxxxxx>
SUSE Labs, CR
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