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

From: Alex Shi
Date: Thu Feb 24 2011 - 19:52:35 EST

Jan Kara 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?
The original drop is 30%.
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.


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