Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757584AbZKYPpT (ORCPT ); Wed, 25 Nov 2009 10:45:19 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1753978AbZKYPpS (ORCPT ); Wed, 25 Nov 2009 10:45:18 -0500 Received: from mx2.mail.elte.hu ([157.181.151.9]:39144 "EHLO mx2.mail.elte.hu" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753347AbZKYPpR (ORCPT ); Wed, 25 Nov 2009 10:45:17 -0500 Date: Wed, 25 Nov 2009 16:44:52 +0100 From: Ingo Molnar To: Thomas Gleixner Cc: Jakub Jelinek , Andrew Haley , "H.J. Lu" , rostedt@goodmis.org, "H. Peter Anvin" , LKML , Andrew Morton , Heiko Carstens , feng.tang@intel.com, Peter Zijlstra , Frederic Weisbecker , David Daney , Richard Guenther , gcc , Linus Torvalds Subject: Re: [PATCH][GIT PULL][v2.6.32] tracing/x86: Add check to detect GCC messing with mcount prologue Message-ID: <20091125154452.GA9456@elte.hu> References: <1258694593.22249.1012.camel@gandalf.stny.rr.com> <1258736456.22249.1032.camel@gandalf.stny.rr.com> <4B06EF6F.2050507@redhat.com> <6dc9ffc80911220138y15bfa91agccf5c29f1c30e09a@mail.gmail.com> <4B0972C9.302@redhat.com> <6dc9ffc80911221530t38d83cf6je739743c8d756667@mail.gmail.com> <4B0BF119.4070704@redhat.com> <20091124150604.GJ22813@hs20-bc2-1.build.redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.20 (2009-08-17) X-ELTE-SpamScore: 0.0 X-ELTE-SpamLevel: X-ELTE-SpamCheck: no X-ELTE-SpamVersion: ELTE 2.0 X-ELTE-SpamCheck-Details: score=0.0 required=5.9 tests=none autolearn=no SpamAssassin version=3.2.5 _SUMMARY_ Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1084 Lines: 28 * Thomas Gleixner wrote: > On Tue, 24 Nov 2009, Jakub Jelinek wrote: > > > On Tue, Nov 24, 2009 at 03:55:49PM +0100, Thomas Gleixner wrote: > > > > you should compile your code with -maccumulate-outgoing-args, and there's > > > > no need to use -mtune=generic. Is that right? > > > > > > Seems to work. What other side effects has that ? > > > > Faster code, significant increase in code size though. Note that on many > > architectures it is the only supported model. > > Just checked on the affected -marchs. The increase in code size is > about 3% which is not that bad and definitely acceptable for the > tracing case. Will zap the -mtune=generic patch and use > -maccumulate-outgoing-args instead. hm, 3% sounds quite large :( dyn-ftrace is enabled in distro configs, so 3% is a big deal IMO. Ingo -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/