Re: [PATCH RFC] x86: avoid atomic operation in test_and_set_bit_lockif possible
From: Ingo Molnar
Date: Thu Mar 24 2011 - 16:51:10 EST
* Andi Kleen <andi@xxxxxxxxxxxxxx> wrote:
> Ingo Molnar <mingo@xxxxxxx> writes:
> >
> > One good way to see cache bounces is to run a misses/accesses ratio profile:
> >
> > perf top -e cache-misses -e cache-references --count-filter 10
> >
> > Note the two events: this runs a 'weighted' profile, you'll see (LLC)
> > cache-misses of a function relative to cache-references it does, a
> > misses/references ratio in essence.
>
> If anyone does this on a Nehalem please only use 2.6.39-rc*+ which
> includes the offcore patches. Anything before that will get you complete
> bogus numbers.
In that case the second example i quoted can be used:
perf top -e L1-dcache-store-misses -e L1-dcache-stores --count-filter 10
Or:
perf top -e L1-dcache-load-misses -e L1-dcache-loads --count-filter 10
Thanks,
Ingo
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