From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Chris Friesen" Subject: Re: [patch] Performance Counters for Linux, v2 Date: Tue, 09 Dec 2008 13:51:36 -0600 Message-ID: <493ECC48.6060107@nortel.com> References: <20081208012211.GA23106@elte.hu> <7c86c4470812082237ne58c814s7218cc663f3b49e9@mail.gmail.com> <20081209134636.GA1926@elte.hu> <493E9F3E.3020902@nortel.com> <20081209190254.GA27833@elte.hu> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Return-path: Received: from zcars04e.nortel.com ([47.129.242.56]:57903 "EHLO zcars04e.nortel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753841AbYLITwF (ORCPT ); Tue, 9 Dec 2008 14:52:05 -0500 In-Reply-To: <20081209190254.GA27833@elte.hu> Sender: linux-arch-owner@vger.kernel.org List-ID: To: Ingo Molnar Cc: eranian@gmail.com, linux-kernel@vger.kernel.org, Thomas Gleixner , linux-arch@vger.kernel.org, Andrew Morton , Eric Dumazet , Robert Richter , Arjan van de Veen , Peter Anvin , Peter Zijlstra , Steven Rostedt , David Miller , Paul Mackerras , Paolo Ciarrocchi Ingo Molnar wrote: > * Chris Friesen wrote: >> Regardless of sampling method, don't you still want some way to >> enable/disable the various counters as close to simultaneously as >> possible? > > If it's about counter control for the monitored task, then we sure could > do something about that. (apps/libraries could thus select a subset of > functions to profile/measure, runtime, etc.) > > If it's about counter control for the profiler/debugger, i'm not sure how > useful that is - do you have a good usecase for it? I'm sure that others could give more usecases, but I was thinking about cases like "I want to test _these_ multiple metrics simultaneously over _this_ specific section of code". In a case like this, it seems desirable to start/stop the various performance counters as close together as possible, especially if the section of code being tested is short. Chris