From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-7.1 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 21F06C433DF for ; Thu, 28 May 2020 14:37:26 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id EC0D8207F5 for ; Thu, 28 May 2020 14:37:25 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1590676646; bh=9zKbvCTU1zpIf1hXyspIWo1sTvWjTI9Sv5au6DTe2/A=; h=Date:From:To:Cc:Subject:References:In-Reply-To:List-ID:From; b=TmErO0ThR9QnMYe4yvDqGMgkZMSjg+wEU3KxkUjUKf6lPSaahfjGxqDxXTIe1jCk0 RQcdPniUukXcuEzCzAufA8uCx5SecTJcVO4ek5UGeExbblT5IA6+cSODzYMM8sUKYY 6MkyEERmMF3VvfAGJP6gP5f8S6aU5OinCF+YTb64= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726865AbgE1OhZ (ORCPT ); Thu, 28 May 2020 10:37:25 -0400 Received: from mail.kernel.org ([198.145.29.99]:40774 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725768AbgE1OhW (ORCPT ); Thu, 28 May 2020 10:37:22 -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 A6FBD207D3; Thu, 28 May 2020 14:37:21 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1590676642; bh=9zKbvCTU1zpIf1hXyspIWo1sTvWjTI9Sv5au6DTe2/A=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=youo3qj1doLzHlyZ9m5p+QpHesq0JDPsPSQZQ8h/YLw2cpJyFREkbwVnXqSkTjn70 vCqwYoD+/O6LUwHcUCuF8TzXGf3118s6oKYxChb5zhVJUGXJfLF1NqlIld+SZQwq5v dBdP3OQAlRXGaR9S1eanipSg9knRNrmppoIzCxIE= Received: by quaco.ghostprotocols.net (Postfix, from userid 1000) id 91AB440AFD; Thu, 28 May 2020 11:37:19 -0300 (-03) Date: Thu, 28 May 2020 11:37:19 -0300 From: Arnaldo Carvalho de Melo To: Adrian Hunter Cc: Jiri Olsa , Andi Kleen , linux-kernel@vger.kernel.org, Mathieu Poirier Subject: Re: [PATCH 1/2] perf record: Respect --no-switch-events Message-ID: <20200528143719.GG16490@kernel.org> References: <20200528120859.21604-1-adrian.hunter@intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20200528120859.21604-1-adrian.hunter@intel.com> X-Url: http://acmel.wordpress.com Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Em Thu, May 28, 2020 at 03:08:58PM +0300, Adrian Hunter escreveu: > Context switch events are added automatically by Intel PT and Coresight. > Make it possible to suppress them. That is useful for tracing the > scheduler without the disturbance that the switch event processing > creates. > > Example: > > Prerequisites: > > $ which perf > ~/bin/perf > $ sudo setcap "cap_sys_rawio,cap_sys_admin,cap_sys_ptrace,cap_syslog,cap_ipc_lock=ep" ~/bin/perf > $ sudo chmod +r /proc/kcore > > Before: > > $ perf record --no-switch-events --kcore -a -e intel_pt//k -- sleep 0.001 > [ perf record: Woken up 1 times to write data ] > [ perf record: Captured and wrote 0.938 MB perf.data ] > $ perf script -D | grep PERF_RECORD_SWITCH | wc -l > 572 > > After: > > $ perf record --no-switch-events --kcore -a -e intel_pt//k -- sleep 0.001 > Warning: > Intel Processor Trace decoding will not be possible except for kernel tracing! > [ perf record: Woken up 1 times to write data ] > [ perf record: Captured and wrote 0.838 MB perf.data ] > $ perf script -D | grep PERF_RECORD_SWITCH | wc -l > 0 > > $ sudo chmod go-r /proc/kcore > $ sudo setcap -r ~/bin/perf Thanks, tested as root and applied. - Arnaldo > Signed-off-by: Adrian Hunter > --- > tools/perf/Documentation/perf-record.txt | 4 +++- > tools/perf/arch/arm/util/cs-etm.c | 3 ++- > tools/perf/arch/x86/util/intel-pt.c | 3 ++- > tools/perf/builtin-record.c | 5 +++-- > tools/perf/util/record.h | 6 ++++++ > 5 files changed, 16 insertions(+), 5 deletions(-) > > diff --git a/tools/perf/Documentation/perf-record.txt b/tools/perf/Documentation/perf-record.txt > index 561ef55743e2..97b1a866ab22 100644 > --- a/tools/perf/Documentation/perf-record.txt > +++ b/tools/perf/Documentation/perf-record.txt > @@ -458,7 +458,9 @@ This option sets the time out limit. The default value is 500 ms. > > --switch-events:: > Record context switch events i.e. events of type PERF_RECORD_SWITCH or > -PERF_RECORD_SWITCH_CPU_WIDE. > +PERF_RECORD_SWITCH_CPU_WIDE. In some cases (e.g. Intel PT or CoreSight) > +switch events will be enabled automatically, which can be suppressed by > +by the option --no-switch-events. > > --clang-path=PATH:: > Path to clang binary to use for compiling BPF scriptlets. > diff --git a/tools/perf/arch/arm/util/cs-etm.c b/tools/perf/arch/arm/util/cs-etm.c > index 607499b41bea..cea5e33d61d2 100644 > --- a/tools/perf/arch/arm/util/cs-etm.c > +++ b/tools/perf/arch/arm/util/cs-etm.c > @@ -265,7 +265,8 @@ static int cs_etm_recording_options(struct auxtrace_record *itr, > ptr->evlist = evlist; > ptr->snapshot_mode = opts->auxtrace_snapshot_mode; > > - if (perf_can_record_switch_events()) > + if (!record_opts__no_switch_events(opts) && > + perf_can_record_switch_events()) > opts->record_switch_events = true; > > evlist__for_each_entry(evlist, evsel) { > diff --git a/tools/perf/arch/x86/util/intel-pt.c b/tools/perf/arch/x86/util/intel-pt.c > index fdb917fcf511..3fc547769707 100644 > --- a/tools/perf/arch/x86/util/intel-pt.c > +++ b/tools/perf/arch/x86/util/intel-pt.c > @@ -779,7 +779,8 @@ static int intel_pt_recording_options(struct auxtrace_record *itr, > * Per-cpu recording needs sched_switch events to distinguish different > * threads. > */ > - if (have_timing_info && !perf_cpu_map__empty(cpus)) { > + if (have_timing_info && !perf_cpu_map__empty(cpus) && > + !record_opts__no_switch_events(opts)) { > if (perf_can_record_switch_events()) { > bool cpu_wide = !target__none(&opts->target) && > !target__has_task(&opts->target); > diff --git a/tools/perf/builtin-record.c b/tools/perf/builtin-record.c > index 02d85f4e4517..dc6d5ba2fff8 100644 > --- a/tools/perf/builtin-record.c > +++ b/tools/perf/builtin-record.c > @@ -2490,8 +2490,9 @@ static struct option __record_options[] = { > "Record namespaces events"), > OPT_BOOLEAN(0, "all-cgroups", &record.opts.record_cgroup, > "Record cgroup events"), > - OPT_BOOLEAN(0, "switch-events", &record.opts.record_switch_events, > - "Record context switch events"), > + OPT_BOOLEAN_SET(0, "switch-events", &record.opts.record_switch_events, > + &record.opts.record_switch_events_set, > + "Record context switch events"), > OPT_BOOLEAN_FLAG(0, "all-kernel", &record.opts.all_kernel, > "Configure all used events to run in kernel space.", > PARSE_OPT_EXCLUSIVE), > diff --git a/tools/perf/util/record.h b/tools/perf/util/record.h > index dce6332f5071..84dbbc3f0204 100644 > --- a/tools/perf/util/record.h > +++ b/tools/perf/util/record.h > @@ -36,6 +36,7 @@ struct record_opts { > bool record_namespaces; > bool record_cgroup; > bool record_switch_events; > + bool record_switch_events_set; > bool all_kernel; > bool all_user; > bool kernel_callchains; > @@ -77,4 +78,9 @@ extern struct option *record_options; > > int record__parse_freq(const struct option *opt, const char *str, int unset); > > +static inline bool record_opts__no_switch_events(const struct record_opts *opts) > +{ > + return opts->record_switch_events_set && !opts->record_switch_events; > +} > + > #endif // _PERF_RECORD_H > -- > 2.17.1 > -- - Arnaldo