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=-13.0 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,NICE_REPLY_A, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_SANE_1 autolearn=unavailable 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 7E85EC433DF for ; Tue, 4 Aug 2020 14:49:22 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 70980206DA for ; Tue, 4 Aug 2020 14:49:22 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729385AbgHDOs5 (ORCPT ); Tue, 4 Aug 2020 10:48:57 -0400 Received: from mga04.intel.com ([192.55.52.120]:46371 "EHLO mga04.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729289AbgHDOs4 (ORCPT ); Tue, 4 Aug 2020 10:48:56 -0400 IronPort-SDR: tsVZ/tjcKwsoxZgJuff7q/SM3d6XUIw56F2RHxSPBILGzF7fpsz5a3ChOCp6W7ckrGtvOZ5ZSH WwTV+vZiaJIg== X-IronPort-AV: E=McAfee;i="6000,8403,9703"; a="149767250" X-IronPort-AV: E=Sophos;i="5.75,434,1589266800"; d="scan'208";a="149767250" X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from fmsmga005.fm.intel.com ([10.253.24.32]) by fmsmga104.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 04 Aug 2020 07:48:55 -0700 IronPort-SDR: 6DZxYlE1bs/rSa4hs8oiEQ56aoyt3MJIAYK6vqhTugUjtPXoKO++yNMEsfd226X65H46AnaOv9 uDeI3Z2sIcPA== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.75,434,1589266800"; d="scan'208";a="492923456" Received: from ahunter-desktop.fi.intel.com (HELO [10.237.72.73]) ([10.237.72.73]) by fmsmga005.fm.intel.com with ESMTP; 04 Aug 2020 07:48:50 -0700 Subject: Re: [PATCH v2 4/5] perf record: Don't clear event's period if set by a term To: Ian Rogers Cc: Peter Zijlstra , Ingo Molnar , Arnaldo Carvalho de Melo , Mark Rutland , Alexander Shishkin , Jiri Olsa , Namhyung Kim , Alexei Starovoitov , Daniel Borkmann , Martin KaFai Lau , Song Liu , Yonghong Song , Andrii Nakryiko , John Fastabend , KP Singh , Andi Kleen , Athira Rajeev , LKML , Networking , bpf , Stephane Eranian References: <20200728085734.609930-1-irogers@google.com> <20200728085734.609930-5-irogers@google.com> <969ef797-59ea-69d0-24b9-33bcdff106a1@intel.com> From: Adrian Hunter Organization: Intel Finland Oy, Registered Address: PL 281, 00181 Helsinki, Business Identity Code: 0357606 - 4, Domiciled in Helsinki Message-ID: <86324041-aafb-f556-eda7-6250ba678f24@intel.com> Date: Tue, 4 Aug 2020 17:48:26 +0300 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.10.0 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit Sender: bpf-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: bpf@vger.kernel.org On 4/08/20 4:33 pm, Ian Rogers wrote: > On Tue, Aug 4, 2020 at 3:08 AM Adrian Hunter wrote: >> >> On 28/07/20 11:57 am, Ian Rogers wrote: >>> If events in a group explicitly set a frequency or period with leader >>> sampling, don't disable the samples on those events. >>> >>> Prior to 5.8: >>> perf record -e '{cycles/period=12345000/,instructions/period=6789000/}:S' >> >> Might be worth explaining this use-case some more. >> Perhaps add it to the leader sampling documentation for perf-list. >> >>> would clear the attributes then apply the config terms. In commit >>> 5f34278867b7 leader sampling configuration was moved to after applying the >>> config terms, in the example, making the instructions' event have its period >>> cleared. >>> This change makes it so that sampling is only disabled if configuration >>> terms aren't present. >>> >>> Fixes: 5f34278867b7 ("perf evlist: Move leader-sampling configuration") >>> Signed-off-by: Ian Rogers >>> --- >>> tools/perf/util/record.c | 28 ++++++++++++++++++++-------- >>> 1 file changed, 20 insertions(+), 8 deletions(-) >>> >>> diff --git a/tools/perf/util/record.c b/tools/perf/util/record.c >>> index a4cc11592f6b..01d1c6c613f7 100644 >>> --- a/tools/perf/util/record.c >>> +++ b/tools/perf/util/record.c >>> @@ -2,6 +2,7 @@ >>> #include "debug.h" >>> #include "evlist.h" >>> #include "evsel.h" >>> +#include "evsel_config.h" >>> #include "parse-events.h" >>> #include >>> #include >>> @@ -38,6 +39,9 @@ static void evsel__config_leader_sampling(struct evsel *evsel, struct evlist *ev >>> struct perf_event_attr *attr = &evsel->core.attr; >>> struct evsel *leader = evsel->leader; >>> struct evsel *read_sampler; >>> + struct evsel_config_term *term; >>> + struct list_head *config_terms = &evsel->config_terms; >>> + int term_types, freq_mask; >>> >>> if (!leader->sample_read) >>> return; >>> @@ -47,16 +51,24 @@ static void evsel__config_leader_sampling(struct evsel *evsel, struct evlist *ev >>> if (evsel == read_sampler) >>> return; >>> >>> + /* Determine the evsel's config term types. */ >>> + term_types = 0; >>> + list_for_each_entry(term, config_terms, list) { >>> + term_types |= 1 << term->type; >>> + } >>> /* >>> - * Disable sampling for all group members other than the leader in >>> - * case the leader 'leads' the sampling, except when the leader is an >>> - * AUX area event, in which case the 2nd event in the group is the one >>> - * that 'leads' the sampling. >>> + * Disable sampling for all group members except those with explicit >>> + * config terms or the leader. In the case of an AUX area event, the 2nd >>> + * event in the group is the one that 'leads' the sampling. >>> */ >>> - attr->freq = 0; >>> - attr->sample_freq = 0; >>> - attr->sample_period = 0; >>> - attr->write_backward = 0; >>> + freq_mask = (1 << EVSEL__CONFIG_TERM_FREQ) | (1 << EVSEL__CONFIG_TERM_PERIOD); >>> + if ((term_types & freq_mask) == 0) { >> >> It would be nicer to have a helper e.g. >> >> if (!evsel__have_config_term(evsel, FREQ) && >> !evsel__have_config_term(evsel, PERIOD)) { > > Sure. The point of doing it this way was to avoid repeatedly iterating > over the config term list. But perhaps it is premature optimization > >>> + attr->freq = 0; >>> + attr->sample_freq = 0; >>> + attr->sample_period = 0; >> >> If we are not sampling, then maybe we should also put here: >> >> attr->write_backward = 0; >> >>> + } >> >> Then, if we are sampling this evsel shouldn't the backward setting >> match the leader? e.g. >> >> if (attr->sample_freq) >> attr->write_backward = leader->core.attr.write_backward; > > Perhaps that should be a follow up change? This change is trying to > make the behavior match the previous behavior. Sure > > Thanks, > Ian > >>> + if ((term_types & (1 << EVSEL__CONFIG_TERM_OVERWRITE)) == 0) >>> + attr->write_backward = 0; >>> >>> /* >>> * We don't get a sample for slave events, we make them when delivering >>> >>