Re: [performance bug] kernel building regression on 64 LCPUs machine

[Jeff Moyer]

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.
>> ÂOK 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:
>> ÂI'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.

Cheers,
Jeff
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