Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753427AbbFLUwj (ORCPT ); Fri, 12 Jun 2015 16:52:39 -0400 Received: from mail-qk0-f177.google.com ([209.85.220.177]:34355 "EHLO mail-qk0-f177.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751170AbbFLUwh (ORCPT ); Fri, 12 Jun 2015 16:52:37 -0400 Message-ID: <557B4691.7090304@gmail.com> Date: Fri, 12 Jun 2015 14:52:33 -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> <557AFDB1.7030902@gmail.com> <37D7C6CF3E00A74B8858931C1DB2F07701876834@SHSMSX103.ccr.corp.intel.com> <557B16C4.7000000@gmail.com> <37D7C6CF3E00A74B8858931C1DB2F07701876CB2@SHSMSX103.ccr.corp.intel.com> <557B3309.4080002@gmail.com> <37D7C6CF3E00A74B8858931C1DB2F07701876D60@SHSMSX103.ccr.corp.intel.com> In-Reply-To: <37D7C6CF3E00A74B8858931C1DB2F07701876D60@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 Content-Length: 1617 Lines: 42 On 6/12/15 2:39 PM, Liang, Kan wrote: > Here are the test results. > Please note that I get "synthesized threads took..." after the test case exit. > It means both way have the same issue. Got it. So what you really mean is launching perf on an already running process perf never finishes initializing. There are several types of problems like this. For example on a sparc system with a 1024 cpus if I launch perf (top or record) after starting a kernel build with make -j 1024 the build finishes before perf starts collecting samples. ie., it never finishes walking /proc until the build is complete. task_diag does not solve that problem either and in general the procps tools can't handle it either (ps or top for example). For your test case what happens if you run: perf record -- test-app Is perf overloaded with mmap samples? does it keep up or do you have to jack the mmap size (-m arg)? > > [perf]$ sudo ./perf record -a -- usleep 1 > synthesized threads took 278.780762 sec > [ perf record: Woken up 1 times to write data ] > [ perf record: Captured and wrote 0.617 MB perf.data (7974 samples) ] > > [perf]$ sudo ./perf record -a --no-task_diag -- usleep 1 > synthesized threads took 315.612403 sec > [ perf record: Woken up 1 times to write data ] > [ perf record: Captured and wrote 0.443 MB perf.data (2754 samples) ] > ok. Thanks, David -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/