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

From: Jan Kara
Date: Thu Feb 24 2011 - 07:13:49 EST

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.

Jan Kara <jack@xxxxxxx>