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From: David Miller <davem@davemloft.net>
To: mingo@elte.hu
Cc: paulus@samba.org, linux-kernel@vger.kernel.org,
	tglx@linutronix.de, linux-arch@vger.kernel.org,
	akpm@linux-foundation.org, eranian@googlemail.com,
	dada1@cosmosbay.com, robert.richter@amd.com, arjan@infradead.org,
	hpa@zytor.com, a.p.zijlstra@chello.nl, rostedt@goodmis.org
Subject: Re: [patch] Performance Counters for Linux, v2
Date: Mon, 08 Dec 2008 04:02:04 -0800 (PST)	[thread overview]
Message-ID: <20081208.040204.139217002.davem@davemloft.net> (raw)
In-Reply-To: <20081208113318.GA14723@elte.hu>

From: Ingo Molnar <mingo@elte.hu>
Date: Mon, 8 Dec 2008 12:33:18 +0100

> Your whole statistical argument that group readout is a must-have for 
> precision is fundamentally flawed as well: counters _themselves_, as used 
> by most applications, by their nature, are a statistical sample to begin 
> with. There's way too many hardware events to track each of them 
> unintrusively - so this type of instrumentation is _all_ sampling based, 
> and fundamentally so. (with a few narrow exceptions such as single-event 
> interrupts for certain rare event types)

There are a lot of people who are going to fundamentally
disagree with this, myself included.

A lot of things are being stated about what people do with this stuff,
but I think there are people working longer in this area who quite
possibly know a lot better.  But they were blindsided by this new work
instead of being consulted, which was pretty unnice.

  reply	other threads:[~2008-12-08 12:02 UTC|newest]

Thread overview: 31+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2008-12-08  1:22 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 [this message]
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
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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