From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752860Ab0IFMnl (ORCPT ); Mon, 6 Sep 2010 08:43:41 -0400 Received: from mx3.mail.elte.hu ([157.181.1.138]:42063 "EHLO mx3.mail.elte.hu" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751146Ab0IFMnk (ORCPT ); Mon, 6 Sep 2010 08:43:40 -0400 Date: Mon, 6 Sep 2010 14:43:30 +0200 From: Ingo Molnar To: Avi Kivity , Tom Zanussi , =?iso-8859-1?Q?Fr=E9d=E9ric?= Weisbecker , Steven Rostedt , Arnaldo Carvalho de Melo Cc: Peter Zijlstra , linux-perf-users@vger.kernel.org, linux-kernel Subject: Re: disabling group leader perf_event Message-ID: <20100906124330.GA22314@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> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <4C84D77B.6040600@redhat.com> 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: 0.4941] Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org * Avi Kivity wrote: > > Being able to make histograms in-kernel has been on the todo list > > for a long while, its just that I never could come up with a sane > > interface.. :/ > > Interesting, I thought it was just me. > > One option is to keep the existing filter interface, but recognize > those cases and optimize the implementation. Sort of like a compiler > can optimize a large dense switch statement to a jump table. Yes. The filter engine is a safe, in-kernel interpreted language in the making. The C syntax was chosen because it's close to the heart of every kernel developer. It might make sense to bring this concept a few steps further. Looks rather complex but also rather cool ... Thanks, Ingo