Date: Mon, 12 Aug 2013 18:11:37 +0200
From: Peter Zijlstra <peterz@infradead.org>
To: Andi Kleen <andi@firstfloor.org>
Cc: "H. Peter Anvin" <hpa@linux.intel.com>,
        Steven Rostedt <rostedt@goodmis.org>,
        LKML <linux-kernel@vger.kernel.org>, gcc <gcc@gcc.gnu.org>,
        Linus Torvalds <torvalds@linux-foundation.org>,
        Ingo Molnar <mingo@kernel.org>,
        Mathieu Desnoyers <mathieu.desnoyers@efficios.com>,
        Thomas Gleixner <tglx@linutronix.de>,
        David Daney <ddaney.cavm@gmail.com>,
        Behan Webster <behanw@converseincode.com>
Subject: Re: [RFC] gcc feature request: Moving blocks into sections
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On Mon, Aug 12, 2013 at 09:02:02AM -0700, Andi Kleen wrote:
> "H. Peter Anvin" <hpa@linux.intel.com> writes:
> 
> > However, I would really like to
> > understand what the value is.
> 
> Probably very little. When I last looked at it, the main overhead in
> perf currently seems to be backtraces and the ring buffer, not this
> code.

backtraces do indeed blow and make pretty much everything else
irrelevant, but when not using them the branch forest was significant
when I last looked at it.
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