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[23.128.96.18]) by mx.google.com with ESMTP id m3si429542eje.124.2020.10.13.11.27.41; Tue, 13 Oct 2020 11:28:04 -0700 (PDT) Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) client-ip=23.128.96.18; Authentication-Results: mx.google.com; dkim=pass header.i=@kernel.org header.s=default header.b=bVBpOOgN; spf=pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org; dmarc=pass (p=NONE sp=NONE dis=NONE) header.from=kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727743AbgJMMhx (ORCPT + 99 others); Tue, 13 Oct 2020 08:37:53 -0400 Received: from mail.kernel.org ([198.145.29.99]:48670 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726492AbgJMMhx (ORCPT ); Tue, 13 Oct 2020 08:37:53 -0400 Received: from quaco.ghostprotocols.net (unknown [179.97.37.151]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id CBE31223BE; Tue, 13 Oct 2020 12:37:51 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1602592672; bh=mPyc3FZzyfNNgR0Hx0NpRLMwr3Vc1dhRpM/n4pWj7gY=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=bVBpOOgNIGwk/b0mgpwcPuUZpBOissW12ADHkk8cI4tQh1529H9SDPYaSumMcqOvK erKsPCZUeDuULIqW4ZtR4K+FCQxWyYo4zYvnVErO3CsL5BIPt8q3BTWVfu05JFNCBa VGh8QEvbYwLxDGe/epb9Lbb7FrkcLnf2rCTfUUo8= Received: by quaco.ghostprotocols.net (Postfix, from userid 1000) id 00DE4403AC; Tue, 13 Oct 2020 09:37:48 -0300 (-03) Date: Tue, 13 Oct 2020 09:37:48 -0300 From: Arnaldo Carvalho de Melo To: Joel Fernandes Cc: Namhyung Kim , linux-kernel , Alexander Shishkin , Ingo Molnar , Jiri Olsa , Mark Rutland , Peter Zijlstra Subject: Re: [PATCH] perf: sched: Show start of latency as well Message-ID: <20201013123748.GC1063281@kernel.org> References: <20200925235634.4089867-1-joel@joelfernandes.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: X-Url: http://acmel.wordpress.com Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Em Sat, Sep 26, 2020 at 11:45:39AM -0400, Joel Fernandes escreveu: > On Sat, Sep 26, 2020 at 10:10 AM Namhyung Kim wrote: > [...] > > On Sat, Sep 26, 2020 at 8:56 AM Joel Fernandes (Google) > > wrote: > > > > > > perf sched latency is really useful at showing worst-case latencies that task > > > encountered since wakeup. However it shows only the end of the latency. Often > > > times the start of a latency is interesting as it can show what else was going > > > on at the time to cause the latency. I certainly myself spending a lot of time > > > backtracking to the start of the latency in "perf sched script" which wastes a > > > lot of time. > > > > > > This patch therefore adds a new column "Max delay start". Considering this, > > > also rename "Maximum delay at" to "Max delay end" as its easier to understand. > > > > Oh, I thought we print start time not the end time. I think it's better > > to print start time but others may think differently. > > Right, glad you think so too. > > > Actually we can calculate the start time from the end time and the > > latency but it'd be convenient if the tool does that for us (as they are > > printed in different units). > > Correct, but as you mention it is more burdensome to calculate each time. > > > Then the remaining concern is the screen > > width (of 114 or 115?) but I think it should be fine for most of us. > > It is 114 without the patch and 140 with it. I tried my best to trim > it a little. It fits fine on my screen with the patch. So I think we > should be good! So, what do you think of removing all the redundant info so that we can get it in a more compact way, i.e.: | Delays ----------------------------------------------------------------------------------------------------- Task | Runtime | Switches | Avg | Max | Max start | Max end | ----------------------------------------------------------------------------------------------------- MediaScannerSer:11936 | 651.296 ms | 67978 | 0.113 ms | 77.250 ms | 477.691360 s | 477.768610 s audio@2.0-servi:(3) | 0.000 ms | 3440 | 0.034 ms | 72.267 ms | 477.697051 s | 477.769318 s AudioOut_1D:8112 | 0.000 ms | 2588 | 0.083 ms | 64.020 ms | 477.710740 s | 477.774760 s Time-limited te:14973 | 7966.090 ms | 24807 | 0.073 ms | 15.563 ms | 477.162746 s | 477.178309 s surfaceflinger:8049 | 9.680 ms | 603 | 0.063 ms | 13.275 ms | 476.931791 s | 476.945067 s HeapTaskDaemon:(3) | 1588.830 ms | 7040 | 0.065 ms | 6.880 ms | 473.666043 s | 473.672922 s mount-passthrou:(3) | 1370.809 ms | 68904 | 0.011 ms | 6.524 ms | 478.090630 s | 478.097154 s ReferenceQueueD:(3) | 11.794 ms | 1725 | 0.014 ms | 6.521 ms | 476.119782 s | 476.126303 s writer:14077 | 18.410 ms | 1427 | 0.036 ms | 6.131 ms | 474.169675 s | 474.175805 s > > Acked-by: Namhyung Kim > > Thanks, Namyhung! > > - Joel > > > > Signed-off-by: Joel Fernandes (Google) > > > > > > > > > --- > > > A sample output can be seen after applying patch: > > > https://hastebin.com/raw/ivinimaler > > > > > > tools/perf/builtin-sched.c | 24 ++++++++++++++---------- > > > 1 file changed, 14 insertions(+), 10 deletions(-) > > > > > > diff --git a/tools/perf/builtin-sched.c b/tools/perf/builtin-sched.c > > > index 459e4229945e..2791da1fe5f7 100644 > > > --- a/tools/perf/builtin-sched.c > > > +++ b/tools/perf/builtin-sched.c > > > @@ -130,7 +130,8 @@ struct work_atoms { > > > struct thread *thread; > > > struct rb_node node; > > > u64 max_lat; > > > - u64 max_lat_at; > > > + u64 max_lat_start; > > > + u64 max_lat_end; > > > u64 total_lat; > > > u64 nb_atoms; > > > u64 total_runtime; > > > @@ -1096,7 +1097,8 @@ add_sched_in_event(struct work_atoms *atoms, u64 timestamp) > > > atoms->total_lat += delta; > > > if (delta > atoms->max_lat) { > > > atoms->max_lat = delta; > > > - atoms->max_lat_at = timestamp; > > > + atoms->max_lat_start = atom->wake_up_time; > > > + atoms->max_lat_end = timestamp; > > > } > > > atoms->nb_atoms++; > > > } > > > @@ -1322,7 +1324,7 @@ static void output_lat_thread(struct perf_sched *sched, struct work_atoms *work_ > > > int i; > > > int ret; > > > u64 avg; > > > - char max_lat_at[32]; > > > + char max_lat_start[32], max_lat_end[32]; > > > > > > if (!work_list->nb_atoms) > > > return; > > > @@ -1344,13 +1346,14 @@ static void output_lat_thread(struct perf_sched *sched, struct work_atoms *work_ > > > printf(" "); > > > > > > avg = work_list->total_lat / work_list->nb_atoms; > > > - timestamp__scnprintf_usec(work_list->max_lat_at, max_lat_at, sizeof(max_lat_at)); > > > + timestamp__scnprintf_usec(work_list->max_lat_start, max_lat_start, sizeof(max_lat_start)); > > > + timestamp__scnprintf_usec(work_list->max_lat_end, max_lat_end, sizeof(max_lat_end)); > > > > > > - printf("|%11.3f ms |%9" PRIu64 " | avg:%9.3f ms | max:%9.3f ms | max at: %13s s\n", > > > + printf("|%11.3f ms |%9" PRIu64 " | avg:%8.3f ms | max:%8.3f ms | max start: %12s s | max end: %12s s\n", > > > (double)work_list->total_runtime / NSEC_PER_MSEC, > > > work_list->nb_atoms, (double)avg / NSEC_PER_MSEC, > > > (double)work_list->max_lat / NSEC_PER_MSEC, > > > - max_lat_at); > > > + max_lat_start, max_lat_end); > > > } > > > > > > static int pid_cmp(struct work_atoms *l, struct work_atoms *r) > > > @@ -3118,7 +3121,8 @@ static void __merge_work_atoms(struct rb_root_cached *root, struct work_atoms *d > > > list_splice(&data->work_list, &this->work_list); > > > if (this->max_lat < data->max_lat) { > > > this->max_lat = data->max_lat; > > > - this->max_lat_at = data->max_lat_at; > > > + this->max_lat_start = data->max_lat_start; > > > + this->max_lat_end = data->max_lat_end; > > > } > > > zfree(&data); > > > return; > > > @@ -3157,9 +3161,9 @@ static int perf_sched__lat(struct perf_sched *sched) > > > perf_sched__merge_lat(sched); > > > perf_sched__sort_lat(sched); > > > > > > - printf("\n -----------------------------------------------------------------------------------------------------------------\n"); > > > - printf(" Task | Runtime ms | Switches | Average delay ms | Maximum delay ms | Maximum delay at |\n"); > > > - printf(" -----------------------------------------------------------------------------------------------------------------\n"); > > > + printf("\n -------------------------------------------------------------------------------------------------------------------------------------------\n"); > > > + printf(" Task | Runtime ms | Switches | Avg delay ms | Max delay ms | Max delay start | Max delay end |\n"); > > > + printf(" -------------------------------------------------------------------------------------------------------------------------------------------\n"); > > > > > > next = rb_first_cached(&sched->sorted_atom_root); > > > > > > -- > > > 2.28.0.709.gb0816b6eb0-goog -- - Arnaldo