From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753312Ab1EQH44 (ORCPT ); Tue, 17 May 2011 03:56:56 -0400 Received: from mx3.mail.elte.hu ([157.181.1.138]:41138 "EHLO mx3.mail.elte.hu" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752565Ab1EQH4y (ORCPT ); Tue, 17 May 2011 03:56:54 -0400 Date: Tue, 17 May 2011 09:56:35 +0200 From: Ingo Molnar To: Andi Kleen Cc: Thomas Gleixner , Andy Lutomirski , x86@kernel.org, linux-kernel@vger.kernel.org, Linus Torvalds , "David S. Miller" , Eric Dumazet , Peter Zijlstra , Borislav Petkov Subject: Re: [PATCH v4 0/6] Micro-optimize vclock_gettime Message-ID: <20110517075635.GA22093@elte.hu> References: <20110516160943.GC25898@one.firstfloor.org> <20110516164939.GD25898@one.firstfloor.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20110516164939.GD25898@one.firstfloor.org> User-Agent: Mutt/1.5.20 (2009-08-17) X-ELTE-SpamScore: -2.0 X-ELTE-SpamLevel: X-ELTE-SpamCheck: no X-ELTE-SpamVersion: ELTE 2.0 X-ELTE-SpamCheck-Details: score=-2.0 required=5.9 tests=BAYES_00 autolearn=no SpamAssassin version=3.3.1 -2.0 BAYES_00 BODY: Bayes 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 * Andi Kleen wrote: > > And unless you or someone else changes the primitive state of the > > kernel, framepointers are going to stay simply because removing them > > breaks profiling backtraces when the hit is inside vread(). > > This doesn't work anyways because the glibc stub code calling vgettimeofday > normally doesn't set up a frame pointer frame. But we at least get a callchain back to that point. Also, Thomas's point remains: you can whine about framepointers and you can try to slowly sabotage proper backtraces (nasty and sleazy tactic you are using there btw), or you can help out bring sane dwarf support to the kernel. Thanks, Ingo