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From: Ingo Molnar <mingo@kernel.org>
To: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Arnaldo Carvalho de Melo <acme@infradead.org>,
	linux-kernel@vger.kernel.org,
	Arjan van de Ven <arjan@infradead.org>,
	David Ahern <dsahern@gmail.com>,
	Frederic Weisbecker <fweisbec@gmail.com>,
	Mike Galbraith <efault@gmx.de>, Namhyung Kim <namhyung@gmail.com>,
	Paul Mackerras <paulus@samba.org>,
	Peter Zijlstra <peterz@infradead.org>,
	Stephane Eranian <eranian@google.com>
Subject: Re: [GIT PULL 0/8] Annotation weekly ponies delivery
Date: Mon, 14 May 2012 09:05:07 +0200	[thread overview]
Message-ID: <20120514070507.GB27980@gmail.com> (raw)
In-Reply-To: <CA+55aFzGAokE5htNFhkoRxT5bK1_5=uofkC5xZipTtiawSh_hA@mail.gmail.com>


* Linus Torvalds <torvalds@linux-foundation.org> wrote:

> On Sat, May 12, 2012 at 2:25 PM, Arnaldo Carvalho de Melo
> <acme@infradead.org> wrote:
> >
> > Didn't notice it, but then I'm not updating the kernel that frequently,
> > will check on this Sandy Bridge nobo (i7-2920XM).
> 
> I think SNB has problems with PEBS and cycles anyway. I have a 
> westmere machine that I use for profiling for that reason.

I have a pre-westmere Nehalem that I use most for perf testing - 
that one appears to be working well both with default cycles and 
with cycles:pp. Will test on a Westmere.

btw., Arnaldo, could we make cycles:pp the default event on perf 
record and perf top? We have the new AMD IBS code in perf/core 
queued up for v3.5, which is roughly equivalent to cycles:p on 
Intel CPUs, so if we standardize on cycles:pp we'll get improved 
skidless (and on Intel pre-SB CPUs, precise) profiling output by 
default.

While at it I'd also suggest increasing the default sampling 
frequency, from 1000 Hz per CPU to at least 4Khz auto-freq or so 
- this should work well all across the board I think. CPUs are 
getting faster and command/app run times are getting shorter, 
1Khz is a bit low IMO.

Thanks,

	Ingo

  reply	other threads:[~2012-05-14  7:05 UTC|newest]

Thread overview: 23+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2012-05-12 19:52 [GIT PULL 0/8] Annotation weekly ponies delivery Arnaldo Carvalho de Melo
2012-05-12 19:53 ` [PATCH 1/8] perf annotate: Use raw form for register indirect call instructions Arnaldo Carvalho de Melo
2012-05-12 19:53 ` [PATCH 2/8] perf annotate: Resolve symbols using objdump comment Arnaldo Carvalho de Melo
2012-05-12 19:53 ` [PATCH 3/8] perf annotate: Resolve symbols using objdump comment for single op ins Arnaldo Carvalho de Melo
2012-05-12 19:53 ` [PATCH 4/8] perf annotate: Augment lock instruction output Arnaldo Carvalho de Melo
2012-05-12 19:53 ` [PATCH 5/8] perf annotate: Introduce ->free() method in ins_ops Arnaldo Carvalho de Melo
2012-05-12 19:53 ` [PATCH 6/8] perf annotate browser: Count the numbers of jump sources to a target Arnaldo Carvalho de Melo
2012-05-12 19:53 ` [PATCH 7/8] perf annotate browser: Show 'jumpy' functions Arnaldo Carvalho de Melo
2012-05-12 19:53 ` [PATCH 8/8] perf annotate browser: Add key bindings help window Arnaldo Carvalho de Melo
2012-05-12 20:40 ` [GIT PULL 0/8] Annotation weekly ponies delivery Linus Torvalds
2012-05-12 21:25   ` Arnaldo Carvalho de Melo
2012-05-12 22:29     ` Linus Torvalds
2012-05-14  7:05       ` Ingo Molnar [this message]
2012-05-14 11:13   ` Peter Zijlstra
2012-05-14 11:55     ` Ingo Molnar
2012-05-14 15:06       ` Namhyung Kim
2012-05-15  4:48         ` Namhyung Kim
2012-05-15 10:32         ` Peter Zijlstra
2012-05-15 14:44           ` Namhyung Kim
2012-05-15 17:07             ` Peter Zijlstra
2012-05-16  5:57               ` Namhyung Kim
2012-05-16  8:19                 ` Namhyung Kim
2012-05-17  0:13                 ` Namhyung Kim

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