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[2620:137:e000::1:20]) by mx.google.com with ESMTP id k13-20020a170906054d00b00997cc1ef3d3si805570eja.375.2023.08.03.19.21.08; Thu, 03 Aug 2023 19:21:31 -0700 (PDT) Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) client-ip=2620:137:e000::1:20; Authentication-Results: mx.google.com; spf=pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org; dmarc=fail (p=QUARANTINE sp=QUARANTINE dis=NONE) header.from=huawei.com Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233076AbjHDCKg (ORCPT + 99 others); Thu, 3 Aug 2023 22:10:36 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:36442 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231478AbjHDCKV (ORCPT ); Thu, 3 Aug 2023 22:10:21 -0400 Received: from szxga01-in.huawei.com (szxga01-in.huawei.com [45.249.212.187]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 77C13A3; Thu, 3 Aug 2023 19:10:20 -0700 (PDT) Received: from kwepemm600003.china.huawei.com (unknown [172.30.72.57]) by szxga01-in.huawei.com (SkyGuard) with ESMTP id 4RH8Gl06vNztRpT; Fri, 4 Aug 2023 10:06:54 +0800 (CST) Received: from localhost.localdomain (10.67.174.95) by kwepemm600003.china.huawei.com (7.193.23.202) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2507.27; Fri, 4 Aug 2023 10:10:17 +0800 From: Yang Jihong To: , , , , , , , , , , , , , , , CC: Subject: [PATCH v5 4/7] perf record: Track sideband events for all CPUs when tracing selected CPUs Date: Fri, 4 Aug 2023 02:07:38 +0000 Message-ID: <20230804020741.99806-5-yangjihong1@huawei.com> X-Mailer: git-send-email 2.30.GIT In-Reply-To: <20230804020741.99806-1-yangjihong1@huawei.com> References: <20230804020741.99806-1-yangjihong1@huawei.com> MIME-Version: 1.0 X-Originating-IP: [10.67.174.95] X-ClientProxiedBy: dggems706-chm.china.huawei.com (10.3.19.183) To kwepemm600003.china.huawei.com (7.193.23.202) X-CFilter-Loop: Reflected X-Spam-Status: No, score=-1.9 required=5.0 tests=BAYES_00, RCVD_IN_DNSWL_BLOCKED,RCVD_IN_MSPIKE_H5,RCVD_IN_MSPIKE_WL, SPF_HELO_NONE,SPF_PASS,T_SCC_BODY_TEXT_LINE,URIBL_BLOCKED autolearn=ham autolearn_force=no version=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on lindbergh.monkeyblade.net Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org X-getmail-retrieved-from-mailbox: INBOX X-GMAIL-THRID: 1773263326921576925 X-GMAIL-MSGID: 1773263326921576925 User space tasks can migrate between CPUs, we need to track side-band events for all CPUs. The specific scenarios are as follows: CPU0 CPU1 perf record -C 0 start taskA starts to be created and executed -> PERF_RECORD_COMM and PERF_RECORD_MMAP events only deliver to CPU1 ...... | migrate to CPU0 | Running on CPU0 <----------/ ... perf record -C 0 stop Now perf samples the PC of taskA. However, perf does not record the PERF_RECORD_COMM and PERF_RECORD_MMAP events of taskA. Therefore, the comm and symbols of taskA cannot be parsed. The solution is to record sideband events for all CPUs when tracing selected CPUs. Because this modifies the default behavior, add related comments to the perf record man page. The sys_perf_event_open invoked is as follows: # perf --debug verbose=3 record -e cpu-clock -C 1 true Opening: cpu-clock ------------------------------------------------------------ perf_event_attr: type 1 (PERF_TYPE_SOFTWARE) size 136 config 0 (PERF_COUNT_SW_CPU_CLOCK) { sample_period, sample_freq } 4000 sample_type IP|TID|TIME|CPU|PERIOD|IDENTIFIER read_format ID|LOST disabled 1 inherit 1 freq 1 sample_id_all 1 exclude_guest 1 ------------------------------------------------------------ sys_perf_event_open: pid -1 cpu 1 group_fd -1 flags 0x8 = 5 Opening: dummy:u ------------------------------------------------------------ perf_event_attr: type 1 (PERF_TYPE_SOFTWARE) size 136 config 0x9 (PERF_COUNT_SW_DUMMY) { sample_period, sample_freq } 1 sample_type IP|TID|TIME|CPU|IDENTIFIER read_format ID|LOST inherit 1 exclude_kernel 1 exclude_hv 1 mmap 1 comm 1 task 1 sample_id_all 1 exclude_guest 1 mmap2 1 comm_exec 1 ksymbol 1 bpf_event 1 ------------------------------------------------------------ sys_perf_event_open: pid -1 cpu 0 group_fd -1 flags 0x8 = 6 sys_perf_event_open: pid -1 cpu 1 group_fd -1 flags 0x8 = 7 sys_perf_event_open: pid -1 cpu 2 group_fd -1 flags 0x8 = 9 sys_perf_event_open: pid -1 cpu 3 group_fd -1 flags 0x8 = 10 sys_perf_event_open: pid -1 cpu 4 group_fd -1 flags 0x8 = 11 sys_perf_event_open: pid -1 cpu 5 group_fd -1 flags 0x8 = 12 sys_perf_event_open: pid -1 cpu 6 group_fd -1 flags 0x8 = 13 sys_perf_event_open: pid -1 cpu 7 group_fd -1 flags 0x8 = 14 Signed-off-by: Yang Jihong Acked-by: Adrian Hunter --- tools/perf/Documentation/perf-record.txt | 3 ++ tools/perf/builtin-record.c | 44 +++++++++++++++++++++++- 2 files changed, 46 insertions(+), 1 deletion(-) diff --git a/tools/perf/Documentation/perf-record.txt b/tools/perf/Documentation/perf-record.txt index 680396c56bd1..dac53ece51ab 100644 --- a/tools/perf/Documentation/perf-record.txt +++ b/tools/perf/Documentation/perf-record.txt @@ -388,6 +388,9 @@ comma-separated list with no space: 0,1. Ranges of CPUs are specified with -: 0- In per-thread mode with inheritance mode on (default), samples are captured only when the thread executes on the designated CPUs. Default is to monitor all CPUs. +User space tasks can migrate between CPUs, so when tracing selected CPUs, +a dummy event is created to track sideband for all CPUs. + -B:: --no-buildid:: Do not save the build ids of binaries in the perf.data files. This skips diff --git a/tools/perf/builtin-record.c b/tools/perf/builtin-record.c index 3ff9d972225e..e575b5e295a2 100644 --- a/tools/perf/builtin-record.c +++ b/tools/perf/builtin-record.c @@ -908,10 +908,44 @@ static int record__config_off_cpu(struct record *rec) return off_cpu_prepare(rec->evlist, &rec->opts.target, &rec->opts); } +static bool record__tracking_system_wide(struct record *rec) +{ + struct record_opts *opts = &rec->opts; + struct evlist *evlist = rec->evlist; + struct evsel *evsel; + + /* + * If all (non-dummy) evsel have exclude_user, + * system_wide is not needed. + * + * all_kernel and all_user will overwrite exclude_kernel and + * exclude_user of attr in evsel__config(), here need to check + * all the three items. + * + * Sideband system wide if one of the following conditions is met: + * + * - all_user is set, and there is a non-dummy event + * - all_user and all_kernel are not set, and there is + * a non-dummy event without exclude_user + */ + if (opts->all_kernel) + return false; + + evlist__for_each_entry(evlist, evsel) { + if (!evsel__is_dummy_event(evsel)) { + if (opts->all_user || !evsel->core.attr.exclude_user) + return true; + } + } + + return false; +} + static int record__config_tracking_events(struct record *rec) { struct record_opts *opts = &rec->opts; struct evlist *evlist = rec->evlist; + bool system_wide = false; struct evsel *evsel; /* @@ -921,7 +955,15 @@ static int record__config_tracking_events(struct record *rec) */ if (opts->target.initial_delay || target__has_cpu(&opts->target) || perf_pmus__num_core_pmus() > 1) { - evsel = evlist__findnew_tracking_event(evlist, false); + + /* + * User space tasks can migrate between CPUs, so when tracing + * selected CPUs, sideband for all CPUs is still needed. + */ + if (!!opts->target.cpu_list && record__tracking_system_wide(rec)) + system_wide = true; + + evsel = evlist__findnew_tracking_event(evlist, system_wide); if (!evsel) return -ENOMEM;