From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755752Ab1KQIWW (ORCPT ); Thu, 17 Nov 2011 03:22:22 -0500 Received: from mail-yw0-f46.google.com ([209.85.213.46]:47378 "EHLO mail-yw0-f46.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755510Ab1KQIWV convert rfc822-to-8bit (ORCPT ); Thu, 17 Nov 2011 03:22:21 -0500 MIME-Version: 1.0 In-Reply-To: <4EBCF0EB.8080304@gmail.com> References: <1320670457-2633428-1-git-send-email-avagin@openvz.org> <1320670457-2633428-3-git-send-email-avagin@openvz.org> <1320839740.13360.11.camel@twins> <4EBCF0EB.8080304@gmail.com> Date: Thu, 17 Nov 2011 11:22:20 +0300 Message-ID: Subject: Re: [PATCH 2/7] event: don't divide events if it has field period From: Andrew Wagin To: Peter Zijlstra Cc: Andrew Vagin , linux-kernel@vger.kernel.org, Arun Sharma , Paul Mackerras , Ingo Molnar , Arnaldo Carvalho de Melo , devel@openvz.org Content-Type: text/plain; charset=KOI8-R Content-Transfer-Encoding: 8BIT Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hello Peter, 11 ноября 2011 г. 13:54 пользователь Andrew Vagin написал: > On 11/09/2011 03:55 PM, Peter Zijlstra wrote: >> >> On Mon, 2011-11-07 at 15:54 +0300, Andrew Vagin wrote: >>> >>> This patch solves the following problem: >>> >>> Now some samples may be lost due to throttling. The number of samples is >>> restricted by sysctl_perf_event_sample_rate/HZ.  A trace event is >>> divided on some samples according to event's period.  I don't sure, that >>> we should generate more than one sample on each trace event. I think the >>> better way to use SAMPLE_PERIOD. >> >> It would be yes, but this code predates that, also it needs to work even >> if the user doesn't provide SAMPLE_PERIOD. I have not understood exactly what I should do now. I'm going to send the third version of this patches. New version contains only a small fix according with the comment for path 4/7. In new version I am not going to fix the problem about which we discussed early. I have some reasons for it: * It's another task. My decision is more effective for my task and I believe that exists many cases where my decision may be suitable. I want to say, that it may be in kernel, event if the problem would not exist at all. * __perf_count() has been broken for a long time and nobody reports this problem, so we can say, that the problem isn't urgent. * Only few events sched:sched_stat_* are affected by this problem. * I am not sure, that we should to solve this problem. The "problem" may be not a problem at all. We have ability to customize sample_period and we have events about that some events were throttled. If you have any objection, send them to me.