Messages in this thread | | | Date | Mon, 1 Jul 2013 00:00:04 +0200 | From | Borislav Petkov <> | Subject | Re: [PATCH] x86: Use asm-goto to implement mutex fast path on x86-64 |
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On Sat, Jun 29, 2013 at 04:56:30PM -0700, Wedson Almeida Filho wrote: > On Fri, Jun 28, 2013 at 7:09 AM, Borislav Petkov <bp@alien8.de> wrote: > > > Btw, do we have any perf data showing any improvements from this patch? > > I wrote a simple test the measures the time it takes to acquire and > release an uncontended mutex (i.e., we always take the fast path) > 100k times. I ran it a few times, the original code averages > 2.743436ms, and the new code averages 2.101098ms, so it's about 23% improvement.
Microbenchmark results tend to be misleading in such situations. Rather, it would be much closer to reality if you traced a real workload like a simple kernel build, for example, with and without your patch.
I.e., something like
perf stat --repeat 5 ./build-kernel.sh
and take a look at what the perfcouters are saying in both cases.
> I also think the code looks cleaner this way.
No doubt.
-- Regards/Gruss, Boris.
Sent from a fat crate under my desk. Formatting is fine. --
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