Re: [PATCH RFC] x86: avoid atomic operation in test_and_set_bit_lock if possible

Ingo Molnar
2011-03-24T20:51:06Z

* Andi Kleen <andi@firstfloor.org> wrote:

> Ingo Molnar <mingo@elte.hu> 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