Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753420Ab0AYKOS (ORCPT ); Mon, 25 Jan 2010 05:14:18 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1753276Ab0AYKOR (ORCPT ); Mon, 25 Jan 2010 05:14:17 -0500 Received: from bombadil.infradead.org ([18.85.46.34]:33219 "EHLO bombadil.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752769Ab0AYKOQ (ORCPT ); Mon, 25 Jan 2010 05:14:16 -0500 Subject: Re: linux-next: add utrace tree From: Peter Zijlstra To: ananth@in.ibm.com Cc: Ingo Molnar , Kyle Moffett , Stephen Rothwell , 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, Linus Torvalds , Thomas Gleixner In-Reply-To: <20100125045908.GB4895@in.ibm.com> References: <20100121170541.7425ff10.akpm@linux-foundation.org> <20100122182827.GA13185@redhat.com> <20100122200129.GG22003@redhat.com> <20100122221348.GA4263@redhat.com> <20100123112333.GA15455@elte.hu> <20100125045908.GB4895@in.ibm.com> Content-Type: text/plain; charset="UTF-8" Date: Mon, 25 Jan 2010 11:13:46 +0100 Message-ID: <1264414426.4283.1644.camel@laptop> Mime-Version: 1.0 X-Mailer: Evolution 2.28.1 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 881 Lines: 19 On Mon, 2010-01-25 at 10:29 +0530, Ananth N Mavinakayanahalli wrote: > - Extend perf; would perf then use utrace underneath? Or would one have > to redo some of what utrace already does for thread level control? No, perf is about monitoring/tracing not modifying. Its about minimal interference, the very opposite of what ptrace/utrace is about. >From a perf POV if you need to stop a task (changing it scheduling state) you've lost. Furthermore, despite the name utrace isn't about tracing at all, its a full blown debugging infrastructure which completely multiplexes the task state, not something perf is interested in at all. -- 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/