From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753004Ab3EFMEf (ORCPT ); Mon, 6 May 2013 08:04:35 -0400 Received: from mx1.redhat.com ([209.132.183.28]:11040 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752463Ab3EFMEe (ORCPT ); Mon, 6 May 2013 08:04:34 -0400 Date: Mon, 6 May 2013 14:04:11 +0200 From: Jiri Olsa To: Namhyung Kim Cc: Arnaldo Carvalho de Melo , Peter Zijlstra , Paul Mackerras , Ingo Molnar , Namhyung Kim , LKML , Steven Rostedt , Frederic Weisbecker , David Ahern , Stephane Eranian Subject: Re: [PATCH 09/14] perf ftrace: Add 'record' sub-command Message-ID: <20130506120411.GA6035@krava.brq.redhat.com> References: <1366705872-12132-1-git-send-email-namhyung@kernel.org> <1366705872-12132-10-git-send-email-namhyung@kernel.org> <20130424141241.GG971@krava.brq.redhat.com> <87bo939lgt.fsf@sejong.aot.lge.com> <87mws8990n.fsf@sejong.aot.lge.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <87mws8990n.fsf@sejong.aot.lge.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, May 06, 2013 at 10:44:56AM +0900, Namhyung Kim wrote: > Hi Jiri, > > Sorry for late reply. I've been busy these days. > > On Thu, 25 Apr 2013 15:24:18 +0900, Namhyung Kim wrote: > > On Wed, 24 Apr 2013 16:12:41 +0200, Jiri Olsa wrote: > >> I got following lockup for record command: > >> > >> # ./perf --no-pager ftrace record ls > >> ... > >> hangs > >> > >> in other terminal: > >> > >> # pstack 14237 > >> Thread 2 (Thread 0x7f3f1aa1d700 (LWP 14241)): > >> #0 0x0000003cec20b595 in pthread_cond_wait@@GLIBC_2.3.2 () from /lib64/libpthread.so.0 > >> #1 0x0000000000446ebe in record_ftrace_raw_buffer (arg=0x21f9ce0) at builtin-ftrace.c:451 > >> #2 0x0000003cec207d14 in start_thread () from /lib64/libpthread.so.0 > >> #3 0x0000003cebaf168d in clone () from /lib64/libc.so.6 > >> Thread 1 (Thread 0x7f3f1ba209c0 (LWP 14237)): > >> #0 0x0000003cec208e60 in pthread_join () from /lib64/libpthread.so.0 > >> #1 0x0000000000449c8c in do_ftrace_record (ftrace=ftrace@entry=0x7fff1377d240) at builtin-ftrace.c:682 > >> #2 0x000000000044a57b in __cmd_ftrace_record (argv=0x7fff1377d818, argc=, ftrace=0x7fff1377d240) at builtin-ftrace.c:1535 > >> #3 cmd_ftrace (argc=2, argv=0x7fff1377d818, prefix=) at builtin-ftrace.c:1655 > >> #4 0x000000000041a763 in run_builtin (p=p@entry=0x7d58a0, argc=argc@entry=3, argv=argv@entry=0x7fff1377d818) at perf.c:320 > >> #5 0x0000000000419faf in handle_internal_command (argv=0x7fff1377d818, argc=3) at perf.c:377 > >> #6 run_argv (argv=0x7fff1377d600, argcp=0x7fff1377d60c) at perf.c:421 > >> #7 main (argc=3, argv=0x7fff1377d818) at perf.c:522 > >> > > > > How often can you reproduce it? I can't. :( > > > > But it looks there's a race between cond_wait() and cond_broatcast(). > > I'll take a look at that. > > I think the problem is that a recorder can be blocked if it received a > broadcast signal before calling cond_wait(). So I modified the code to > place signaling ready_cond and waiting start_cond in the same cs. > > Does the patch below fix your problem? yes.. without the patch I get lockup in like 10 minutes with the patch the test is now ok for almost an hour.. jirka