Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754010Ab1ECXMr (ORCPT ); Tue, 3 May 2011 19:12:47 -0400 Received: from mail-ww0-f44.google.com ([74.125.82.44]:51820 "EHLO mail-ww0-f44.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753396Ab1ECXMq (ORCPT ); Tue, 3 May 2011 19:12:46 -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=ZJWboZ05LJlcfLineWViYCwEj3Tb1smkXUXMp7tzM9Dx6Gjsr+Y3kZVgspPzClXEjI i7kPKlgHdWbjBGMIUAV4ubjUmtI7+MrbplXbScIaEcWUOgdGfaGYzv4iHBfDZvz91Jxr OkpZn3H0b5ACarTzaeMz9wr1R62eOMeWtS2Gc= Date: Wed, 4 May 2011 01:12:43 +0200 From: Frederic Weisbecker To: "H. Peter Anvin" Cc: LKML , Ingo Molnar , Peter Zijlstra , Jason Wessel , Thomas Gleixner Subject: Re: [PATCH 3/6] x86: Allow the user not to build hw_breakpoints Message-ID: <20110503231241.GG2678@nowhere> References: <1303923602-2923-1-git-send-email-fweisbec@gmail.com> <1303923602-2923-4-git-send-email-fweisbec@gmail.com> <4DB854AA.6070101@zytor.com> <20110427182633.GB1753@nowhere> <008d59a3-bd23-4cb3-8a73-1640137e3ac4@email.android.com> <20110427195004.GA3654@nowhere> <4DC020D9.3050000@zytor.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <4DC020D9.3050000@zytor.com> User-Agent: Mutt/1.5.20 (2009-06-14) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1178 Lines: 22 On Tue, May 03, 2011 at 08:35:53AM -0700, H. Peter Anvin wrote: > On 04/27/2011 12:50 PM, Frederic Weisbecker wrote: > > On Wed, Apr 27, 2011 at 11:54:17AM -0700, H. Peter Anvin wrote: > >> Why do you have to be able to disable breakpoints to disable perf? That seems seriously backwards, especially since we had breakpoints long before perf... > > > > That started when we implemented breakpoints as counters. Then we realized that > > ptrace had its own scheduling that was somehow duplicating what perf was doing. > > So we have finally unified that under perf. The good point is that archs don't need > > to care much about ptrace breakpoints tracking, just the interface. > > > > But yeah the bad point is that dependency. > > It really is very bad... without breakpoints, you lose almost all > debugging support. Right, so it should be fine for embedded environment to disable breakpoints. It depends on CONFIG_EXPERT now. -- 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/