From: Andi Kleen <andi@firstfloor.org>
To: Ingo Molnar <mingo@elte.hu>
Cc: Jack Steiner <steiner@sgi.com>, Jan Beulich <JBeulich@novell.com>,
Borislav Petkov <bp@amd64.org>,
Peter Zijlstra <a.p.zijlstra@chello.nl>,
Nick Piggin <npiggin@kernel.dk>,
"x86\@kernel.org" <x86@kernel.org>,
Thomas Gleixner <tglx@linutronix.de>,
Andrew Morton <akpm@linux-foundation.org>,
Linus Torvalds <torvalds@linux-foundation.org>,
Ingo Molnar <mingo@redhat.com>,
tee@sgi.com, Nikanth Karthikesan <knikanth@suse.de>,
"linux-kernel\@vger.kernel.org" <linux-kernel@vger.kernel.org>,
"H. Peter Anvin" <hpa@zytor.com>
Subject: Re: [PATCH RFC] x86: avoid atomic operation in test_and_set_bit_lock if possible
Date: Thu, 24 Mar 2011 13:40:49 -0700 [thread overview]
Message-ID: <m2sjucl0a6.fsf@firstfloor.org> (raw)
In-Reply-To: <20110324200010.GB7957@elte.hu> (Ingo Molnar's message of "Thu, 24 Mar 2011 21:00:10 +0100")
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.
BTW with Lin-Ming's memory latency profiling code you can do this much
more directly.
-Andi
--
ak@linux.intel.com -- Speaking for myself only
next prev parent reply other threads:[~2011-03-24 20:42 UTC|newest]
Thread overview: 49+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-03-24 4:56 [PATCH RFC] x86: avoid atomic operation in test_and_set_bit_lock if possible Nikanth Karthikesan
2011-03-24 8:52 ` Jan Beulich
2011-03-24 8:56 ` Ingo Molnar
2011-03-24 14:52 ` Borislav Petkov
2011-03-24 16:48 ` Jan Beulich
2011-03-24 17:19 ` Ingo Molnar
2011-03-25 10:06 ` Jan Beulich
2011-03-25 11:10 ` Ingo Molnar
2011-03-25 12:04 ` Nikanth Karthikesan
2011-03-25 13:12 ` Jack Steiner
2011-03-25 16:29 ` Linus Torvalds
2011-03-25 16:47 ` Jan Beulich
2011-03-25 16:49 ` Jack Steiner
2011-03-24 17:30 ` Jack Steiner
2011-03-24 20:00 ` Ingo Molnar
2011-03-24 20:40 ` Andi Kleen [this message]
2011-03-24 20:50 ` Ingo Molnar
2011-03-24 21:37 ` Andi Kleen
2011-03-24 20:48 ` Eric Dumazet
2011-03-24 20:54 ` Ingo Molnar
2011-03-24 21:02 ` Eric Dumazet
2011-03-24 21:42 ` Andi Kleen
2011-03-24 23:26 ` Linus Torvalds
2011-03-24 23:56 ` Andi Kleen
2011-03-25 5:47 ` Eric Dumazet
2011-03-25 9:32 ` Ingo Molnar
2011-03-25 9:44 ` Eric Dumazet
2011-03-25 9:59 ` Ingo Molnar
2011-03-25 10:50 ` Borislav Petkov
2011-03-25 11:10 ` Peter Zijlstra
2011-03-25 11:11 ` Ingo Molnar
2011-03-25 16:16 ` Robert Richter
2011-03-25 17:22 ` Andi Kleen
2011-03-25 19:26 ` Ingo Molnar
2011-03-25 9:38 ` Eric Dumazet
2011-03-25 20:29 ` Peter Zijlstra
2011-03-26 8:15 ` Eric Dumazet
2011-03-26 9:44 ` Peter Zijlstra
2011-03-26 9:57 ` Ingo Molnar
2011-03-25 9:22 ` Ingo Molnar
2011-03-25 10:21 ` Peter Zijlstra
2011-03-25 16:08 ` Robert Richter
2011-03-25 19:31 ` Ingo Molnar
2011-03-25 17:15 ` Andi Kleen
2011-03-25 19:21 ` Ingo Molnar
2011-03-25 9:35 ` Ingo Molnar
2011-03-24 17:01 ` Linus Torvalds
2011-03-24 17:13 ` Jack Steiner
2011-03-24 18:38 ` Andi Kleen
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