Re: [RFC] - Move call to calc_load()

From: Dimitri Sivanich
Date: Tue Mar 21 2006 - 15:46:09 EST



On Tue, Mar 21, 2006 at 09:36:47PM +0100, Ingo Molnar wrote:
> * Jack Steiner <steiner@xxxxxxx> wrote:
>
> > Here is the patch that I am proposing. This patch is incomplete
> > because it addresses only the IA64 architecture. If this approach is
> > acceptible, I'll update the patch to cover all architectures.
> >
> > Signed-off-by: Jack Steiner <steiner@xxxxxxx>
>
> i agree with your analysis - there is no reason calc_load() should be
> under xtime_lock. I guess no-one noticed this so far because calc_load()
> iterating over hundreds of CPUs isnt too common.

I tested this patch and it works well for eliminating latencies due to
contention for the xtime_lock. Without the patch the latencies are
quite substantial at higher cpu counts.
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