From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S934074AbdJXNZt (ORCPT ); Tue, 24 Oct 2017 09:25:49 -0400 Received: from mail-wr0-f193.google.com ([209.85.128.193]:54775 "EHLO mail-wr0-f193.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S933271AbdJXNZ1 (ORCPT ); Tue, 24 Oct 2017 09:25:27 -0400 X-Google-Smtp-Source: ABhQp+TwSJqjKo/Rxo1dxyXb21POmVlkgQHfMxiY75OTArmZEXjy0L7CY9TuSCUn6y6t7sr26I7HJw== Date: Tue, 24 Oct 2017 15:25:23 +0200 From: Ingo Molnar To: Arnaldo Carvalho de Melo Cc: Jiri Olsa , "Liang, Kan" , "mingo@redhat.com" , "linux-kernel@vger.kernel.org" , "peterz@infradead.org" , "jolsa@kernel.org" , "wangnan0@huawei.com" , "hekuang@huawei.com" , "namhyung@kernel.org" , "alexander.shishkin@linux.intel.com" , "Hunter, Adrian" , "ak@linux.intel.com" Subject: Re: [PATCH V3 0/6] event synthesization multithreading for perf record Message-ID: <20171024132523.u6esbinw4i3vo3yv@gmail.com> References: <1508529934-369393-1-git-send-email-kan.liang@intel.com> <20171023114822.ijbixdkhysinlwqv@gmail.com> <37D7C6CF3E00A74B8858931C1DB2F077537D874E@SHSMSX103.ccr.corp.intel.com> <20171024092200.wef6b66ecmhrvaja@gmail.com> <20171024114755.GA2716@krava> <20171024125944.uswroptykcqrgjox@gmail.com> <20171024130849.GD7045@kernel.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20171024130849.GD7045@kernel.org> User-Agent: NeoMutt/20170609 (1.8.3) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org * Arnaldo Carvalho de Melo wrote: > Em Tue, Oct 24, 2017 at 02:59:44PM +0200, Ingo Molnar escreveu: > > > > * Jiri Olsa wrote: > > > > > I recently made some changes on threaded record, which are based > > > on Namhyungs time* API, which is needed to read/sort the data afterwards > > > > > > but I wasn't able to get any substantial and constant reduce of LOST events > > > and then I got sidetracked and did not finish, but it's in here: > > > > So, in the context of system-wide profiling, the way that would work best I think > > is the following: > > > > thread #0 binds itself to CPU#0 (via sched_setaffinity) and creates a per-CPU event on CPU#0 > > thread #1 binds itself to CPU#1 (via sched_setaffinity) and creates a per-CPU event on CPU#1 > > thread #2 binds itself to CPU#2 (via sched_setaffinity) and creates a per-CPU event on CPU#2 > > Right, that is how I think it should be done as well, and those will > just dump on separate files, in a per session directory, with an extra > file for the session details, in what is now the header. Yes. Also note how easy to examine such a directory structure is - I'd suggest making all the session details textual eventually. I.e. only the ring-buffers should be binary, the rest should be arch-independent text encoding. It's also very extensible. > Later, the same thing happens at processing time, this time we'll have > contention to access global thread state, the need for rounds of > PERF_SAMPLE_TIME based ordering, like what we have now in the > tools/perf/util/ordered-events.[ch] code, etc. > > This works for both 'report', 'script', 'top', 'trace', etc, as is > basically the model we already have. All the work that was done for > refcounting the thread, map, etc as well as locking those rbtrees would > finally be taken full advantage of. Yeah, cool! Thanks, Ingo