Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756775AbZJVVJy (ORCPT ); Thu, 22 Oct 2009 17:09:54 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1756539AbZJVVJx (ORCPT ); Thu, 22 Oct 2009 17:09:53 -0400 Received: from mail-ew0-f208.google.com ([209.85.219.208]:43847 "EHLO mail-ew0-f208.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755639AbZJVVJw (ORCPT ); Thu, 22 Oct 2009 17:09:52 -0400 DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=date:from:to:cc:subject:message-id:references:mime-version :content-type:content-disposition:in-reply-to:user-agent; b=GL/3V7M9VOSRoFx2pnvn/iwZm3JRpA0WvH2RQN2wtyXWeWw2JaIICd0OOZ3iML1g0/ BEawQCqN79yQ/1Mg/4B34FATxEWrMB5yE2MFoYBR6bRKbrLGRl7gpCH1n/EBkj0X3Txa 2KlGZHxtsrWyDiAGGG1KUqBRSVkDDpzmgzqbI= Date: Thu, 22 Oct 2009 23:09:52 +0200 From: Frederic Weisbecker To: Steven Rostedt Cc: Adam Nemet , David Daney , wuzhangjin@gmail.com, Richard Sandiford , linux-kernel@vger.kernel.org, linux-mips@linux-mips.org, Thomas Gleixner , Ralf Baechle , Nicholas Mc Guire Subject: Re: [PATCH -v4 4/9] tracing: add static function tracer support for MIPS Message-ID: <20091022210950.GA10041@nowhere> References: <028867b99ec532b84963a35e7d552becc783cafc.1256135456.git.wuzhangjin@gmail.com> <2f73eae542c47ac5bbb9f7280e6c0271d193e90d.1256135456.git.wuzhangjin@gmail.com> <3f0d3515f74a58f4cfd11e61b62a129fdc21e3a7.1256135456.git.wuzhangjin@gmail.com> <1256138686.18347.3039.camel@gandalf.stny.rr.com> <1256233679.23653.7.camel@falcon> <4AE0A5BE.8000601@caviumnetworks.com> <19168.49354.525249.654494@ropi.home> <1256244726.20866.802.camel@gandalf.stny.rr.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1256244726.20866.802.camel@gandalf.stny.rr.com> User-Agent: Mutt/1.5.18 (2008-05-17) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1315 Lines: 41 On Thu, Oct 22, 2009 at 04:52:06PM -0400, Steven Rostedt wrote: > On Thu, 2009-10-22 at 13:30 -0700, Adam Nemet wrote: > > > > Speaking of performance, -pg also affects the instruction scheduling freedom > > of the compiler in the prologue. With profiling, we limit optimizations not > > to move instructions in and out of the prologue. > > > > Also note that for functions invoked via tail call you won't get an exit > > event. E.g. if bar is tail-called from foo: > > > > foo entered > > bar entered > > foo/bar exited > > > > However, this is not MIPS-specific and you can always disable tail calls > > with -fno-optimize-sibling-calls. Ouch.. > The question is, would bar have a _mcount call? So far, we have not had > any issues with this on either x86 nor PPC. Nothing would prevent that I guess. I mean, we are doing a very specific use of -pg, and common uses wouldn't require to disable the mcount call on bar in this situation, so it's not something that -pg is supposed to care about. > /me knocks on wood. Me too (but not so hard...) -- 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/