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From: "Chris Friesen" <cfriesen@nortel.com>
To: Will Newton <will.newton@gmail.com>
Cc: Ingo Molnar <mingo@elte.hu>,
	eranian@gmail.com, linux-kernel@vger.kernel.org,
	Thomas Gleixner <tglx@linutronix.de>,
	linux-arch@vger.kernel.org,
	Andrew Morton <akpm@linux-foundation.org>,
	Eric Dumazet <dada1@cosmosbay.com>,
	Robert Richter <robert.richter@amd.com>,
	Arjan van de Veen <arjan@infradead.org>,
	Peter Anvin <hpa@zytor.com>,
	Peter Zijlstra <a.p.zijlstra@chello.nl>,
	Steven Rostedt <rostedt@goodmis.org>,
	David Miller <davem@davemloft.net>,
	Paul Mackerras <paulus@samba.org>,
	Paolo Ciarrocchi <paolo.ciarrocchi@gmail.com>
Subject: Re: [patch] Performance Counters for Linux, v2
Date: Tue, 09 Dec 2008 11:35:01 -0600	[thread overview]
Message-ID: <493EAC45.4050704@nortel.com> (raw)
In-Reply-To: <87a5b0800812090846h396523a0kdb2d1ca4b4781851@mail.gmail.com>

Will Newton wrote:
> On Tue, Dec 9, 2008 at 1:46 PM, Ingo Molnar <mingo@elte.hu> wrote:
> 
>> Firstly, sampling "at 1msec intervals" or any fixed period is a _very_
>> wrong mindset - and cross-sampling counters is a similarly wrong mindset.
> 
> If your hardware does not interrupt on overflow I don't think you have
> any choice in the matter. I know such hardware is less than ideal but
> it exists so it should be supported.

I think you could still set up the counters as Ingo describes and then 
sample the counters (as opposed to the program) at a suitable interval 
(chosen such that the counters won't overflow more than once between 
samples).

Chris

  reply	other threads:[~2008-12-09 17:35 UTC|newest]

Thread overview: 31+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2008-12-08  1:22 [patch] Performance Counters for Linux, v2 Ingo Molnar
2008-12-08  1:49 ` Arjan van de Ven
2008-12-08 11:49   ` Ingo Molnar
2009-01-07  7:43     ` Zhang, Yanmin
2009-01-09  1:07       ` Zhang, Yanmin
2008-12-08  3:24 ` Paul Mackerras
2008-12-08 11:33   ` Ingo Molnar
2008-12-08 12:02     ` David Miller
2008-12-08 14:41     ` Andi Kleen
2008-12-08 22:03     ` Paul Mackerras
2008-12-09 13:00       ` Ingo Molnar
2008-12-09 23:00         ` Paul Mackerras
2008-12-08  8:32 ` Corey J Ashford
2008-12-09  6:37 ` stephane eranian
2008-12-09 11:02   ` Ingo Molnar
2008-12-09 11:11     ` David Miller
2008-12-09 11:22       ` Ingo Molnar
2008-12-09 11:29         ` David Miller
2008-12-09 12:14           ` Paolo Ciarrocchi
2008-12-09 13:46   ` Ingo Molnar
2008-12-09 16:39     ` Chris Friesen
2008-12-09 19:02       ` Ingo Molnar
2008-12-09 19:51         ` Chris Friesen
2008-12-09 16:46     ` Will Newton
2008-12-09 17:35       ` Chris Friesen [this message]
2008-12-09 21:16     ` stephane eranian
2008-12-09 22:19     ` Paul Mackerras
2008-12-09 22:40       ` Andi Kleen
2008-12-10  4:44         ` Paul Mackerras
2008-12-10  5:03           ` stephane eranian
2008-12-10 10:26           ` Andi Kleen

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