Date: Fri, 5 Dec 2008 07:00:42 -0800
From: Arjan van de Ven <arjan@infradead.org>
To: David Miller <davem@davemloft.net>
Cc: a.p.zijlstra@chello.nl, paulus@samba.org, mingo@elte.hu,
       tglx@linutronix.de, linux-kernel@vger.kernel.org,
       linux-arch@vger.kernel.org, akpm@linux-foundation.org,
       eranian@googlemail.com, dada1@cosmosbay.com, robert.richter@amd.com,
       hpa@zytor.com, rostedt@goodmis.org
Subject: Re: [patch 0/3] [Announcement] Performance Counters for Linux
Message-ID: <20081205070042.0b8a3ef5@infradead.org>
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On Fri, 05 Dec 2008 00:07:16 -0800 (PST)
David Miller <davem@davemloft.net> wrote:

> These things aren't measuring time, or even just cycles, they
> are measuring things like L2 cache misses, cpu cycles, and
> other similar kinds of events.
> 
> So these counters are going to measure all of the damn crap
> assosciated with doing the read() call as well as the real work
> the task does.

as you said before, not if you do the read() from a thread that's
exempt from the profiling.

-- 
Arjan van de Ven 	Intel Open Source Technology Centre
For development, discussion and tips for power savings, 
visit http://www.lesswatts.org
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