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From: Ingo Molnar <mingo@elte.hu>
To: Steven Rostedt <rostedt@goodmis.org>
Cc: "Peter Zijlstra" <peterz@infradead.org>,
	"Andrew Morton" <akpm@linux-foundation.org>,
	LKML <linux-kernel@vger.kernel.org>,
	"Thomas Gleixner" <tglx@linutronix.de>,
	"Frédéric Weisbecker" <fweisbec@gmail.com>,
	"Arjan van de Ven" <arjan@infradead.org>,
	"Paul Mackerras" <paulus@samba.org>
Subject: Re: [PATCH][GIT PULL] tracing: add function profiler
Date: Sat, 21 Mar 2009 17:26:30 +0100	[thread overview]
Message-ID: <20090321162630.GE11183@elte.hu> (raw)
In-Reply-To: <alpine.DEB.2.00.0903211146430.13615@gandalf.stny.rr.com>


* Steven Rostedt <rostedt@goodmis.org> wrote:

> > If you want exact function count profiling we could try to do 
> > something perf counter based, eg. stick a software counter in 
> > the mcount thingy.
> 
> I'd like to get the function graph version working, in order to 
> calculate the times spent in each funtion, then I can see how we 
> can (if possible) convert it over to perf counters. :-/

the perf counters angle is definitely worth pursuing (for 
completeness of the scheme Peter is working on), but please lets not 
throw the baby out with the bath water: in-kernel histogram 
collection has real value.

It's _much_ faster than any user-space counter-part, especially for 
such things as branch tracing or function tracing.

	Ingo

  reply	other threads:[~2009-03-21 16:27 UTC|newest]

Thread overview: 7+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2009-03-21  4:37 [PATCH][GIT PULL] tracing: add function profiler Steven Rostedt
2009-03-21 11:26 ` Andrew Morton
2009-03-21 11:57   ` Peter Zijlstra
2009-03-21 14:12     ` Ingo Molnar
2009-03-21 15:50     ` Steven Rostedt
2009-03-21 16:26       ` Ingo Molnar [this message]
2009-03-21 15:46   ` Steven Rostedt

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