From: Ingo Molnar <mingo@elte.hu>
To: Steven Rostedt <rostedt@goodmis.org>
Cc: Andi Kleen <andi@firstfloor.org>,
linux-kernel@vger.kernel.org,
Andrew Morton <akpm@linux-foundation.org>,
Thomas Gleixner <tglx@linutronix.de>,
Peter Zijlstra <peterz@infradead.org>,
Theodore Tso <tytso@mit.edu>,
Arjan van de Ven <arjan@infradead.org>,
Steven Rostedt <srostedt@redhat.com>
Subject: Re: [PATCH 4/4] trace: profile all if conditionals
Date: Sun, 23 Nov 2008 22:38:55 +0100 [thread overview]
Message-ID: <20081123213855.GB16613@elte.hu> (raw)
In-Reply-To: <alpine.DEB.1.10.0811231455090.13888@gandalf.stny.rr.com>
* Steven Rostedt <rostedt@goodmis.org> wrote:
> On Sun, 23 Nov 2008, Andi Kleen wrote:
> > Steven Rostedt <rostedt@goodmis.org> writes:
>
> > > This adds a significant amount of overhead and should only be
> > > used by those analyzing their system.
> >
> > Often this can be also done using CPU performance counters. Might
> > be a cheaper option.
>
> I'd love to add an option that could hook into any arch with HW
> support for this. We could dump out the same information, but just a
> different way to gather it. But I'm still ignorant to the use of
> CPU performance counters and how to find which branch matches which
> if.
there's already new ftrace code for this and the patches are done -
stay tuned.
but it wont be a replacement for the soft method (which is more
flexible - the hw can only do 'all or nothing' type of branch
tracing), so it's complementary.
Ingo
next prev parent reply other threads:[~2008-11-23 21:39 UTC|newest]
Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top
2008-11-21 7:12 [PATCH 0/4] trace: profiling branches Steven Rostedt
2008-11-21 7:12 ` [PATCH 1/4] trace: remove extra assign in branch check Steven Rostedt
2008-11-21 7:12 ` [PATCH 2/4] trace: consolidate unlikely and likely profiler Steven Rostedt
2008-11-21 7:12 ` [PATCH 3/4] trace: branch profiling should not print percent without data Steven Rostedt
2008-11-21 7:12 ` [PATCH 4/4] trace: profile all if conditionals Steven Rostedt
2008-11-21 23:20 ` Andrew Morton
2008-11-21 23:33 ` Steven Rostedt
2008-11-23 12:37 ` Ingo Molnar
2008-11-23 15:48 ` Ingo Molnar
2008-11-23 16:07 ` [PATCH] net/wireless/reg.c: fix Ingo Molnar
2008-11-23 19:43 ` [PATCH 4/4] trace: profile all if conditionals Andi Kleen
2008-11-23 19:56 ` Steven Rostedt
2008-11-23 20:24 ` Andi Kleen
2008-11-23 20:32 ` Steven Rostedt
2008-11-23 20:51 ` Andi Kleen
2008-11-23 21:38 ` Ingo Molnar [this message]
2008-11-30 10:58 ` [PATCH 0/4] trace: profiling branches Daniel Walker
2008-11-30 15:19 ` Steven Rostedt
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