From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758080AbZCRDdq (ORCPT ); Tue, 17 Mar 2009 23:33:46 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1757228AbZCRDcy (ORCPT ); Tue, 17 Mar 2009 23:32:54 -0400 Received: from hrndva-omtalb.mail.rr.com ([71.74.56.124]:35368 "EHLO hrndva-omtalb.mail.rr.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754861AbZCRDcv (ORCPT ); Tue, 17 Mar 2009 23:32:51 -0400 Message-Id: <20090318033249.451020891@goodmis.org> References: <20090318031423.981603258@goodmis.org> User-Agent: quilt/0.46-1 Date: Tue, 17 Mar 2009 23:14:26 -0400 From: Steven Rostedt To: linux-kernel@vger.kernel.org Cc: Ingo Molnar , Andrew Morton , Thomas Gleixner , Peter Zijlstra , Frederic Weisbecker , Arjan van de Ven , Miklos Szeredi , Witold Baryluk , Steven Rostedt Subject: [PATCH 3/5] tracing: optimization of branch tracer Content-Disposition: inline; filename=0003-tracing-optimization-of-branch-tracer.patch Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Witold Baryluk Impact: better performance for if branch tracer Use an array to count the hit and misses of a conditional instead of using another conditional. This cuts down on saturation of branch predictions and increases performance of modern pipelined architectures. Signed-off-by: Witold Baryluk Signed-off-by: Steven Rostedt --- include/linux/compiler.h | 6 ++---- 1 files changed, 2 insertions(+), 4 deletions(-) diff --git a/include/linux/compiler.h b/include/linux/compiler.h index d95da10..6faa7e5 100644 --- a/include/linux/compiler.h +++ b/include/linux/compiler.h @@ -68,6 +68,7 @@ struct ftrace_branch_data { unsigned long miss; unsigned long hit; }; + unsigned long miss_hit[2]; }; }; @@ -125,10 +126,7 @@ void ftrace_likely_update(struct ftrace_branch_data *f, int val, int expect); .line = __LINE__, \ }; \ ______r = !!(cond); \ - if (______r) \ - ______f.hit++; \ - else \ - ______f.miss++; \ + ______f.miss_hit[______r]++; \ ______r; \ })) #endif /* CONFIG_PROFILE_ALL_BRANCHES */ -- 1.6.2 --