From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752751Ab0IFMlB (ORCPT ); Mon, 6 Sep 2010 08:41:01 -0400 Received: from mx3.mail.elte.hu ([157.181.1.138]:40867 "EHLO mx3.mail.elte.hu" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751219Ab0IFMlA (ORCPT ); Mon, 6 Sep 2010 08:41:00 -0400 Date: Mon, 6 Sep 2010 14:40:46 +0200 From: Ingo Molnar To: Peter Zijlstra , Tom Zanussi , =?iso-8859-1?Q?Fr=E9d=E9ric?= Weisbecker , Steven Rostedt , Arnaldo Carvalho de Melo Cc: Avi Kivity , linux-perf-users@vger.kernel.org, linux-kernel Subject: Re: disabling group leader perf_event Message-ID: <20100906124046.GA20777@elte.hu> References: <4C84B088.5050003@redhat.com> <1283772256.1930.303.camel@laptop> <4C84D1CE.3070205@redhat.com> <1283774045.1930.341.camel@laptop> <4C84D77B.6040600@redhat.com> <1283776189.1930.380.camel@laptop> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1283776189.1930.380.camel@laptop> User-Agent: Mutt/1.5.20 (2009-08-17) X-ELTE-SpamScore: 1.0 X-ELTE-SpamLevel: s X-ELTE-SpamCheck: no X-ELTE-SpamVersion: ELTE 2.0 X-ELTE-SpamCheck-Details: score=1.0 required=5.9 tests=BAYES_50 autolearn=no SpamAssassin version=3.2.5 1.0 BAYES_50 BODY: Bayesian spam probability is 40 to 60% [score: 0.4568] Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org * Peter Zijlstra wrote: > On Mon, 2010-09-06 at 14:58 +0300, Avi Kivity wrote: > > On 09/06/2010 02:54 PM, Peter Zijlstra wrote: > > > > > >> Basically, to read() all events in one go. I have many of them. > > >> > > >> My current problem is that I have an event (kvm_exit) which I want to > > >> drill down by looking at a field (exit_reason). So I create lots of > > >> separate perf_events with a filter for each reason: > > >> kvm_exit(exit_reason==0), kvm_exit(exit_reason==1), etc. But filters > > >> are fairly slow (can have ~60 such events on AMD), so I want to make > > >> this drill-down optional. > > > Yeah, filters suck. > > > > Any idea why? I saw nothing obvious in the code, except that there > > is lots of it. > > It filters after it does all the hard work of creating the trace > event, instead of before. Btw., that's an implementational property of filters that would be nice to fix. If it's not doable within CPP then outside of it. Ingo