From mboxrd@z Thu Jan 1 00:00:00 1970 From: Tom Tromey Subject: Re: linux-next: add utrace tree Date: Tue, 26 Jan 2010 16:20:22 -0700 Message-ID: References: <20100121013822.28781960.sfr@canb.auug.org.au> <20100122005147.GD22003@redhat.com> <20100121170541.7425ff10.akpm@linux-foundation.org> <20100122182827.GA13185@redhat.com> <20100122200129.GG22003@redhat.com> <20100122221348.GA4263@redhat.com> Reply-To: Tom Tromey Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: In-Reply-To: (Linus Torvalds's message of "Mon, 25 Jan 2010 13:41:57 -0800 (PST)") List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: utrace-devel-bounces@redhat.com Errors-To: utrace-devel-bounces@redhat.com To: Linus Torvalds Cc: Stephen Rothwell , Kyle Moffett , Peter Zijlstra , Peter Zijlstra , Fr??d??ric Weisbecker , Oleg Nesterov , Steven Rostedt , LKML , Arnaldo Carvalho de Melo , "Frank Ch. Eigler" , linux-next@vger.kernel.org, "H. Peter Anvin" , utrace-devel@redhat.com, Thomas Gleixner List-Id: linux-next.vger.kernel.org >>>>> "Linus" == Linus Torvalds writes: Tom> * Support "displaced stepping" in the kernel; I think this would improve Tom> performance when debugging in non-stop mode. Linus> Don't we already do that at least on x86? I don't know. If it does, and gdb does not yet use that, then that would be worth changing. Linus> Or maybe I'm not understanding what displaced stepping means to you. In non-stop mode (where you can stop one thread but leave the others running), gdb wants to have the breakpoints always inserted. So, something must emulate the displaced instruction. Tom From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753535Ab0AZXVf (ORCPT ); Tue, 26 Jan 2010 18:21:35 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1753177Ab0AZXV3 (ORCPT ); Tue, 26 Jan 2010 18:21:29 -0500 Received: from mx1.redhat.com ([209.132.183.28]:44250 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753322Ab0AZXV2 (ORCPT ); Tue, 26 Jan 2010 18:21:28 -0500 From: Tom Tromey To: Linus Torvalds Cc: Kyle Moffett , "Frank Ch. Eigler" , Oleg Nesterov , Andrew Morton , Stephen Rothwell , Peter Zijlstra , Peter Zijlstra , Fr??d??ric Weisbecker , LKML , Steven Rostedt , Arnaldo Carvalho de Melo , linux-next@vger.kernel.org, "H. Peter Anvin" , utrace-devel@redhat.com, Thomas Gleixner Subject: Re: linux-next: add utrace tree References: <20100121013822.28781960.sfr@canb.auug.org.au> <20100122005147.GD22003@redhat.com> <20100121170541.7425ff10.akpm@linux-foundation.org> <20100122182827.GA13185@redhat.com> <20100122200129.GG22003@redhat.com> <20100122221348.GA4263@redhat.com> Reply-To: Tom Tromey X-Attribution: Tom Date: Tue, 26 Jan 2010 16:20:22 -0700 In-Reply-To: (Linus Torvalds's message of "Mon, 25 Jan 2010 13:41:57 -0800 (PST)") Message-ID: User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/23.1 (gnu/linux) MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org >>>>> "Linus" == Linus Torvalds writes: Tom> * Support "displaced stepping" in the kernel; I think this would improve Tom> performance when debugging in non-stop mode. Linus> Don't we already do that at least on x86? I don't know. If it does, and gdb does not yet use that, then that would be worth changing. Linus> Or maybe I'm not understanding what displaced stepping means to you. In non-stop mode (where you can stop one thread but leave the others running), gdb wants to have the breakpoints always inserted. So, something must emulate the displaced instruction. Tom