From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755583AbbFLPlr (ORCPT ); Fri, 12 Jun 2015 11:41:47 -0400 Received: from mail-qg0-f51.google.com ([209.85.192.51]:33552 "EHLO mail-qg0-f51.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753537AbbFLPll (ORCPT ); Fri, 12 Jun 2015 11:41:41 -0400 Message-ID: <557AFDB1.7030902@gmail.com> Date: Fri, 12 Jun 2015 09:41:37 -0600 From: David Ahern User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.10; rv:31.0) Gecko/20100101 Thunderbird/31.7.0 MIME-Version: 1.0 To: "Liang, Kan" , Andi Kleen CC: Arnaldo Carvalho de Melo , "linux-kernel@vger.kernel.org" , "Huang, Ying" Subject: Re: [PATCH 1/1] perf,tools: add time out to force stop endless mmap processing References: <1433922364-22580-1-git-send-email-kan.liang@intel.com> <20150611140614.GC2696@kernel.org> <5579A766.4010504@gmail.com> <20150611184737.GU19417@two.firstfloor.org> <557A28F6.8040603@gmail.com> <37D7C6CF3E00A74B8858931C1DB2F077018767AD@SHSMSX103.ccr.corp.intel.com> In-Reply-To: <37D7C6CF3E00A74B8858931C1DB2F077018767AD@SHSMSX103.ccr.corp.intel.com> Content-Type: text/plain; charset=windows-1252; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 6/12/15 8:42 AM, Liang, Kan wrote: > >> >> On 6/11/15 12:47 PM, Andi Kleen wrote: >>>> Can you elaborate on an example? I don't see how this can happen >>>> reading a maps file. And it does not read maps for all threads only >>>> thread group leaders. >>> >>> This is with a stress test case that generates lots of small mappings >>> at very high speed and frees them again. So the maps file keeps >>> changing faster than the proc reader can keep it and it can end up >>> with a live lock. >> >> Can you pass it along? I'd like to see how the task_diag proposal handles it. >> >> https://github.com/dsahern/linux/commits/task_diag-wip > > Hi David, > > I tried the task_diag on my platform, but it shows error message when I > run perf top. " Message handling failed: rc -1, errno 25". > And it looks perf top failed to get maps information. Not surprising; it's only half-baked. Can you try perf-record? So far that is the only one I have tested. Also, while running that kernel you can build the test programs under tools/testing/selftests/task_diag/ and try task_diag_all. I am away from my dev box at the moment. As I recall you will want to try 'task_diag_all o $pid' or 'task_diag_all a' I take this to mean you don't want to share the test program? I am curious as to how other tools handle this use case.