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From: Andi Kleen <ak@linux.intel.com>
To: arun@sharma-home.net
Cc: Ingo Molnar <mingo@elte.hu>,
	Stephane Eranian <eranian@google.com>,
	Arnaldo Carvalho de Melo <acme@infradead.org>,
	linux-kernel@vger.kernel.org,
	Peter Zijlstra <peterz@infradead.org>,
	Lin Ming <ming.m.lin@intel.com>,
	Arnaldo Carvalho de Melo <acme@redhat.com>,
	Thomas Gleixner <tglx@linutronix.de>,
	Peter Zijlstra <a.p.zijlstra@chello.nl>,
	eranian@gmail.com, Arun Sharma <asharma@fb.com>,
	Linus Torvalds <torvalds@linux-foundation.org>,
	Andrew Morton <akpm@linux-foundation.org>
Subject: Re: [generalized cache events] Re: [PATCH 1/1] perf tools: Add missing user space support for config1/config2
Date: Fri, 22 Apr 2011 10:00:55 -0700	[thread overview]
Message-ID: <20110422170055.GB16607@tassilo.jf.intel.com> (raw)
In-Reply-To: <20110422165007.GA18401@vps.sharma-home.net>

> One could argue that all you need is cycles and instructions. If there is an
> expensive load, you'll see that the load instruction takes many cycles and
> you can infer that it's a cache miss.

That is when you can actually recognize which of the last load instructions
caused the problem. Often skid on Out of order CPUs makes this very hard to 
identify which actual load caused the the long stall (or if they all stalled)

There's a way around it of course using advanced events, but not with
cycles.

> I don't see why exposing all vendor defined events is harmful

Simple: without vendor events you cannot answer a lot of questions.

-Andi

-- 
ak@linux.intel.com -- Speaking for myself only

  reply	other threads:[~2011-04-22 17:01 UTC|newest]

Thread overview: 46+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2011-04-22  8:47 Stephane Eranian
2011-04-22  9:23 ` Ingo Molnar
2011-04-22  9:41   ` Stephane Eranian
2011-04-22 10:52     ` [generalized cache events] " Ingo Molnar
2011-04-22 12:04       ` Stephane Eranian
2011-04-22 13:18         ` Ingo Molnar
2011-04-22 20:31           ` Stephane Eranian
2011-04-22 20:47             ` Ingo Molnar
2011-04-23 12:13               ` Stephane Eranian
2011-04-23 12:49                 ` Ingo Molnar
2011-04-22 21:03             ` Ingo Molnar
2011-04-23 12:27               ` Stephane Eranian
2011-04-22 16:51         ` Andi Kleen
2011-04-22 19:57           ` Ingo Molnar
2011-04-26  9:25           ` Peter Zijlstra
2011-04-22 16:50       ` arun
2011-04-22 17:00         ` Andi Kleen [this message]
2011-04-22 20:30         ` Ingo Molnar
2011-04-22 20:32           ` Ingo Molnar
2011-04-23  0:03             ` Andi Kleen
2011-04-23  7:50               ` Peter Zijlstra
2011-04-23 12:06                 ` Stephane Eranian
2011-04-23 12:36                   ` Ingo Molnar
2011-04-23 13:16                   ` Peter Zijlstra
2011-04-25 18:48                     ` Stephane Eranian
2011-04-25 19:40                     ` Andi Kleen
2011-04-25 19:55                       ` Ingo Molnar
2011-04-24  2:15                   ` Andi Kleen
2011-04-24  2:19                 ` Andi Kleen
2011-04-25 17:41                   ` Ingo Molnar
2011-04-25 18:00                     ` Dehao Chen
     [not found]                     ` <BANLkTiks31-pMJe4zCKrppsrA1d6KanJFA@mail.gmail.com>
2011-04-25 18:05                       ` Ingo Molnar
2011-04-25 18:39                         ` Stephane Eranian
2011-04-25 19:45                           ` Ingo Molnar
2011-04-23  8:02               ` Ingo Molnar
2011-04-23 20:14           ` [PATCH] perf events: Add stalled cycles generic event - PERF_COUNT_HW_STALLED_CYCLES Ingo Molnar
2011-04-24  6:16             ` Arun Sharma
2011-04-25 17:37               ` Ingo Molnar
2011-04-26  9:25               ` Peter Zijlstra
2011-04-26 14:00               ` Ingo Molnar
2011-04-27 11:11               ` Ingo Molnar
2011-04-27 14:47                 ` Arun Sharma
2011-04-27 15:48                   ` Ingo Molnar
2011-04-27 16:27                     ` Ingo Molnar
2011-04-27 19:05                       ` Arun Sharma
2011-04-27 19:03                     ` Arun Sharma

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