Re: High CPU load when machine is idle (related to PROBLEM: Unusually high load average when idle in 2.6.35, 2.6.35.1 and later)

From: tmhikaru
Date: Fri Oct 22 2010 - 22:14:14 EST


On Fri, Oct 22, 2010 at 04:03:42PM -0700, Venkatesh Pallipadi wrote:
> (Sorry about the subjectless earlier mail)
>
> I started making small changes to the code, but none of the change helped much.
> I think the problem with the current code is that, even though idle CPUs
> update load, the fold only happens when one of the CPU is busy
> and we end up taking its load into global load.
>
> So, I tried to simplify things and doing the updates directly from idle loop.
> This is only a test patch, and eventually we need to hook it off somewhere
> else, instead of idle loop and also this is expected work only as x86_64
> right now.
>
> Peter: Do you think something like this will work? loadavg went
> quite on two of my test systems after this change (4 cpu and 24 cpu).
>
> Thanks,
> Venki

I'd really like to be able to help test this, but with a 32bit x86
machine I guess this patch won't do anything for me. How hard would it be to
mangle this into working for my machine or should I just wait?

Tim McGrath

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