Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758039Ab1D0ClX (ORCPT ); Tue, 26 Apr 2011 22:41:23 -0400 Received: from mga11.intel.com ([192.55.52.93]:26402 "EHLO mga11.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755458Ab1D0ClW (ORCPT ); Tue, 26 Apr 2011 22:41:22 -0400 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="4.64,272,1301900400"; d="scan'208";a="914861906" Subject: Re: [PATCH RFC] Fix per-task profiling Re: [PATCH] perf: Allow set output buffer for tasks in the same thread group From: Lin Ming To: Arnaldo Carvalho de Melo Cc: Peter Zijlstra , Ingo Molnar , Tim Blechmann , David Ahern , linux-kernel In-Reply-To: <20110426204401.GB1746@ghostprotocols.net> References: <1303657064.2239.25.camel@localhost> <1303664726.20212.1.camel@twins> <1303738838.2578.1.camel@localhost> <20110425152833.GB32069@ghostprotocols.net> <20110426204401.GB1746@ghostprotocols.net> Content-Type: text/plain; charset="UTF-8" Date: Wed, 27 Apr 2011 10:40:46 +0800 Message-ID: <1303872046.23673.19.camel@minggr.sh.intel.com> Mime-Version: 1.0 X-Mailer: Evolution 2.30.3 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 4655 Lines: 106 On Wed, 2011-04-27 at 04:44 +0800, Arnaldo Carvalho de Melo wrote: > Em Mon, Apr 25, 2011 at 12:28:33PM -0300, Arnaldo Carvalho de Melo escreveu: > > Em Mon, Apr 25, 2011 at 09:40:38PM +0800, Lin Ming escreveu: > > > On Mon, 2011-04-25 at 01:05 +0800, Peter Zijlstra wrote: > > > > On Sun, 2011-04-24 at 22:57 +0800, Lin Ming wrote: > > > > > Currently, kernel only allows an event to redirect its output to other > > > > > events of the same task. > > > > > > This causes PERF_EVENT_IOC_SET_OUTPUT ioctl fails when an event is > > > > > trying to redirect its output to other events in the same thread group. > > > > > Which is exactly what it should do, you should never be allowed to > > > > redirect your events to that of another task, since that other task > > > > might be running on another CPU. > > > > > The buffer code strictly assumes no concurrency, therefore its either > > > > one task or one CPU. > > > > Well, this is not the right fix, then the perf tool code need to be > > > fixed. > > > Yes, I'm working on it. > > Lin, David, Tim, can you please try the two patches attached? > > Tested with: > > [root@felicio ~]# tuna -t 26131 -CP | nl > 1 thread ctxt_switches > 2 pid SCHED_ rtpri affinity voluntary nonvoluntary cmd > 3 26131 OTHER 0 0,1 10814276 2397830 chromium-browse > 4 642 OTHER 0 0,1 14688 0 chromium-browse > 5 26148 OTHER 0 0,1 713602 115479 chromium-browse > 6 26149 OTHER 0 0,1 801958 2262 chromium-browse > 7 26150 OTHER 0 0,1 1271128 248 chromium-browse > 8 26151 OTHER 0 0,1 3 0 chromium-browse > 9 27049 OTHER 0 0,1 36796 9 chromium-browse > 10 618 OTHER 0 0,1 14711 0 chromium-browse > 11 661 OTHER 0 0,1 14593 0 chromium-browse > 12 29048 OTHER 0 0,1 28125 0 chromium-browse > 13 26143 OTHER 0 0,1 2202789 781 chromium-browse > [root@felicio ~]# > > So 11 threads under pid 26131, then: > > [root@felicio ~]# perf record -F 50000 --pid 26131 > > [root@felicio ~]# grep perf_event /proc/`pidof perf`/maps | nl > 1 7fa4a2538000-7fa4a25b9000 rwxs 00000000 00:09 4064 anon_inode:[perf_event] > 2 7fa4a25b9000-7fa4a263a000 rwxs 00000000 00:09 4064 anon_inode:[perf_event] > 3 7fa4a263a000-7fa4a26bb000 rwxs 00000000 00:09 4064 anon_inode:[perf_event] > 4 7fa4a26bb000-7fa4a273c000 rwxs 00000000 00:09 4064 anon_inode:[perf_event] > 5 7fa4a273c000-7fa4a27bd000 rwxs 00000000 00:09 4064 anon_inode:[perf_event] > 6 7fa4a27bd000-7fa4a283e000 rwxs 00000000 00:09 4064 anon_inode:[perf_event] > 7 7fa4a283e000-7fa4a28bf000 rwxs 00000000 00:09 4064 anon_inode:[perf_event] > 8 7fa4a28bf000-7fa4a2940000 rwxs 00000000 00:09 4064 anon_inode:[perf_event] > 9 7fa4a2940000-7fa4a29c1000 rwxs 00000000 00:09 4064 anon_inode:[perf_event] > 10 7fa4a29c1000-7fa4a2a42000 rwxs 00000000 00:09 4064 anon_inode:[perf_event] > 11 7fa4a2a42000-7fa4a2ac3000 rwxs 00000000 00:09 4064 anon_inode:[perf_event] > [root@felicio ~]# > > 11 mmaps, one per thread since we didn't specify any CPU list, so we need one > mmap per thread and: > > [root@felicio ~]# perf record -F 50000 --pid 26131 > ^M > ^C[ perf record: Woken up 79 times to write data ] > [ perf record: Captured and wrote 20.614 MB perf.data (~900639 samples) ] > > [root@felicio ~]# perf report -D | grep PERF_RECORD_SAMPLE | cut -d/ -f2 | cut -d: -f1 | sort -n | uniq -c | sort -nr | nl > 1 371310 26131 > 2 96516 26148 > 3 95694 26149 > 4 95203 26150 > 5 7291 26143 > 6 87 27049 > 7 76 661 > 8 60 29048 > 9 47 618 > 10 43 642 > [root@felicio ~]# > > Ok, one of the threads, 26151 was quiescent, so no samples there, but all the > others are there. > > Then, if I specify one CPU: > > [root@felicio ~]# perf record -F 50000 --pid 26131 --cpu 1 Tested and it works OK. But here is one thing make me confused. I thought that "--pid" and "--cpu" parameters are not allowed to be used at the same time. Otherwise, is it a task event or cpu event? Or does it mean that the event is only monitored when the "task" is running on the specified "cpu"? Thanks, Lin Ming -- 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/