Re: [PATCH 7/8] sched, net: Fixup busy_loop_us_clock()

From: Eliezer Tamir
Date: Thu Nov 28 2013 - 11:49:31 EST


On 26/11/2013 17:57, Peter Zijlstra wrote:
>
> Replace sched_clock() usage with local_clock() which has a bounded
> drift between CPUs (<2 jiffies).
>

Peter,

I have tested this patch and I see a performance regression of about
1.5%.

Maybe it would be better, rather then testing in the fast path, to
simply disallow busy polling altogether when sched_clock_stable is
not true?

Thanks,
Eliezer
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