Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1761220AbZDHQJr (ORCPT ); Wed, 8 Apr 2009 12:09:47 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752705AbZDHQJh (ORCPT ); Wed, 8 Apr 2009 12:09:37 -0400 Received: from mx3.mail.elte.hu ([157.181.1.138]:57377 "EHLO mx3.mail.elte.hu" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752732AbZDHQJg (ORCPT ); Wed, 8 Apr 2009 12:09:36 -0400 Date: Wed, 8 Apr 2009 18:09:15 +0200 From: Ingo Molnar To: Steven Rostedt Cc: linux kernel , Frederic Weisbecker , Tim Bird , Ingo Molnar , Abhishek Sagar , Peter Zijlstra , Thomas Gleixner Subject: Re: [PATCH][GIT PULL] x86, function-graph: only save return values on x86_64 Message-ID: <20090408160915.GD16759@elte.hu> References: <49C936CA.8070800@am.sony.com> <20090324213618.GC5975@nowhere> <20090324214846.GB29509@elte.hu> <20090324215738.GD5975@nowhere> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.18 (2008-05-17) X-ELTE-VirusStatus: clean X-ELTE-SpamScore: -1.5 X-ELTE-SpamLevel: X-ELTE-SpamCheck: no X-ELTE-SpamVersion: ELTE 2.0 X-ELTE-SpamCheck-Details: score=-1.5 required=5.9 tests=BAYES_00 autolearn=no SpamAssassin version=3.2.5 -1.5 BAYES_00 BODY: Bayesian spam probability is 0 to 1% [score: 0.0000] Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2619 Lines: 87 (replying to old mail - working down my awful email backlog) do we still need this for -tip? Ingo * Steven Rostedt wrote: > > Ingo, > > Please pull the latest tip/tracing/function-graph tree, which can be found at: > > git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-2.6-trace.git > tip/tracing/function-graph > > > Steven Rostedt (1): > x86, function-graph: only save return values on x86_64 > > ---- > arch/x86/kernel/entry_64.S | 19 +++---------------- > 1 files changed, 3 insertions(+), 16 deletions(-) > --------------------------- > commit d5b754b2208b1c22691a7cd5d1a65398b5973d74 > Author: Steven Rostedt > Date: Wed Mar 25 14:30:04 2009 -0400 > > x86, function-graph: only save return values on x86_64 > > Impact: speed up > > The return to handler portion of the function graph tracer should only > need to save the return values. The caller already saved off the > registers that the callee can modify. The returning function already > saved the registers it modified. When we call our own trace function > it too will save the registers that the callee must restore. > > There's no reason to save off anything more that the registers used > to return the values. > > Note, I did a complete kernel build with this modification and the > function graph tracer running on x86_64. > > Signed-off-by: Steven Rostedt > > diff --git a/arch/x86/kernel/entry_64.S b/arch/x86/kernel/entry_64.S > index a331ec3..1ac9986 100644 > --- a/arch/x86/kernel/entry_64.S > +++ b/arch/x86/kernel/entry_64.S > @@ -147,27 +147,14 @@ END(ftrace_graph_caller) > GLOBAL(return_to_handler) > subq $80, %rsp > > + /* Save the return values */ > movq %rax, (%rsp) > - movq %rcx, 8(%rsp) > - movq %rdx, 16(%rsp) > - movq %rsi, 24(%rsp) > - movq %rdi, 32(%rsp) > - movq %r8, 40(%rsp) > - movq %r9, 48(%rsp) > - movq %r10, 56(%rsp) > - movq %r11, 64(%rsp) > + movq %rdx, 8(%rsp) > > call ftrace_return_to_handler > > movq %rax, 72(%rsp) > - movq 64(%rsp), %r11 > - movq 56(%rsp), %r10 > - movq 48(%rsp), %r9 > - movq 40(%rsp), %r8 > - movq 32(%rsp), %rdi > - movq 24(%rsp), %rsi > - movq 16(%rsp), %rdx > - movq 8(%rsp), %rcx > + movq 8(%rsp), %rdx > movq (%rsp), %rax > addq $72, %rsp > retq -- 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/