From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752900Ab3KDPiI (ORCPT ); Mon, 4 Nov 2013 10:38:08 -0500 Received: from mx1.redhat.com ([209.132.183.28]:4957 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750791Ab3KDPiH (ORCPT ); Mon, 4 Nov 2013 10:38:07 -0500 Date: Mon, 4 Nov 2013 16:32:16 +0100 From: Jiri Olsa To: David Ahern Cc: linux-kernel@vger.kernel.org, Adrian Hunter , Corey Ashford , Frederic Weisbecker , Ingo Molnar , Namhyung Kim , Paul Mackerras , Peter Zijlstra , Arnaldo Carvalho de Melo Subject: Re: [PATCH 3/3] perf tools: Check maximum frequency rate for record/top Message-ID: <20131104153216.GC2805@krava.brq.redhat.com> References: <1383563173-17466-1-git-send-email-jolsa@redhat.com> <1383563173-17466-4-git-send-email-jolsa@redhat.com> <5277BA84.1090208@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <5277BA84.1090208@gmail.com> User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Nov 04, 2013 at 08:17:24AM -0700, David Ahern wrote: > On 11/4/13, 4:06 AM, Jiri Olsa wrote: > >Adding the check for maximum allowed frequency rate > >defined in following file: > > /proc/sys/kernel/perf_event_max_sample_rate > > > >When we cross the maximum value we fail and display > >detailed error message with advise. > > perf commands should automatically adjust the default frequency too. > If the user did not specify a frequency then this message is going > to be confusing. ok, I'll add that check and probably some warning if we are force to go below the default rate. > > Though the algorithm that keeps lowering the rate should be tweaked as well. yea.. I was thinking putting the max rate back up after some sane period or/plus having 'echo 0 > /proc/sys/kernel/perf_event_max_sample_rate' to disable it completely jirka