From: Ingo Molnar <mingo@elte.hu>
To: Steven Rostedt <rostedt@goodmis.org>
Cc: Andrew Morton <akpm@linux-foundation.org>,
linux-kernel@vger.kernel.org, tglx@linutronix.de,
peterz@infradead.org, tytso@mit.edu, arjan@infradead.org,
srostedt@redhat.com
Subject: Re: [PATCH 4/4] trace: profile all if conditionals
Date: Sun, 23 Nov 2008 13:37:30 +0100 [thread overview]
Message-ID: <20081123123730.GI29663@elte.hu> (raw)
In-Reply-To: <alpine.DEB.1.10.0811211832460.7797@gandalf.stny.rr.com>
* Steven Rostedt <rostedt@goodmis.org> wrote:
>
> On Fri, 21 Nov 2008, Andrew Morton wrote:
> > >
> > > +#define if(cond) if (__builtin_constant_p((cond)) ? !!(cond) : \
> >
> > wheee...
> >
> > Now how are you going to profile ?:, while, for(;expr;), etc? ;)
btw., there's hardware driven branch tracing and profiling in the
works too, which captures all conditionals - including loops. Stay
tuned :)
> I don't know. Give me a few months, I'll figure out a way ;-)
also loops generally have a more static (hence less interesting)
prediction pattern - while for branches we frequently have a "should
this branch be made likely/unlikely in the fastpath" question.
Ingo
next prev parent reply other threads:[~2008-11-23 12:38 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 [this message]
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
2008-11-30 10:58 ` [PATCH 0/4] trace: profiling branches Daniel Walker
2008-11-30 15:19 ` Steven Rostedt
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