From nobody Mon Feb 9 18:01:18 2026 Received: from mail-pj1-f47.google.com (mail-pj1-f47.google.com [209.85.216.47]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 6FEBE1F2372; Wed, 11 Dec 2024 22:25:36 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.216.47 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1733955938; cv=none; b=PQ5QTcjgJX5kTcMsuQ210CosQiS05MVrrsqr9FIOKQB0M7Yih7xHWwj2l7SsYru+JLVMwkGsJ7HvcEEJdOijOVcPyZABAzIFfPdRFbKkaqfTct7Mkjthvz2NrQTSLtL5ykn7p/aJRDhzPSFJTmGcOGYtVUuccT7lW9EubqjNsxg= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1733955938; c=relaxed/simple; bh=CtXvBuHZ10l+NOVrLXSjeix2nXsWB6v1qq32icek0/4=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=OcjTZX0nKdzglk4oVHg6/C6Gpp6DNuCbTiky7/geON9bRElcWV5CSlJSR6GWl0WY+D6VfL91f8O+izyAPsWvzBhWkWjFQJEH2Y2XL5MgKmN2vzt52J9haCTRqiGaIQGf7LS1JXo9cK9OHTuNh4x4GeWsiH5R7URKPkN5tQriTSw= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gmail.com; spf=pass smtp.mailfrom=gmail.com; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b=Jl38I0Tr; arc=none smtp.client-ip=209.85.216.47 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gmail.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=gmail.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="Jl38I0Tr" Received: by mail-pj1-f47.google.com with SMTP id 98e67ed59e1d1-2ee786b3277so5367780a91.1; Wed, 11 Dec 2024 14:25:36 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20230601; t=1733955936; x=1734560736; darn=vger.kernel.org; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:from:to:cc:subject:date :message-id:reply-to; bh=MZXNpS9ontjCFvt+AYY61fDK03PJL203Z521VxrjSJ4=; b=Jl38I0TrD40hOU/bGlAjKvckOoZprynMWq2boG7MZMIL6P7KMkBkJloLeQgskbddTg i4rc1hlRtOqclsAjXEJthRVzSblqCw0/kYRwPAJSC0CxTNyeLVnGnVtSc3FTaELNyyMs pB0Bh9nl7bZha0YoZlqCzBZV4LWfAXEdvldlXXKFcDWWjvtCWJoQJXyrQTMz0p/OH989 5azVDOA7W6va1gsN//c+IBF8DJJ3V0EwvjZ+WUFslkuxiYEoO3LMHiwtL34w+tOv8XY+ rKxw4XFmYnXp4OJ5RIOkWqeOvQkw2991m4CisIYDQtq/TDSRfbJ+v8XTxNwcea3EG6kh XbVQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1733955936; x=1734560736; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:x-gm-message-state:from:to:cc :subject:date:message-id:reply-to; bh=MZXNpS9ontjCFvt+AYY61fDK03PJL203Z521VxrjSJ4=; b=iCW/24RYtTqbITReArtIVhQ2dccmIwiYEk5BztQi0sH62or55agj9HQQzoKQ7vwxu+ Er0y7Mvla7+t9NLh0Ni3hTZCC8W6h8zFxl9awQcWVEJ5TK929YhvzGmVvNDn04Q7EWOF q9+tYev9gapnu4ggFV29L0AGmP7bubVZ+9xii54pgDF7xKoZLx6nqkGUZxjMXLyvlYG7 K5BUcpuK9Zz9lhtVyXFTj/irN3da/cb6u+waKIBorIuVBi8CwirgfKm+POAl6nCt0yiP u9n33daLl1cITwqTE1DTkab3wyXWsk2Or4OKoNRm57HB22Z7v3IqeZqZloRR6EFtO/z7 AEoQ== X-Forwarded-Encrypted: i=1; AJvYcCWBlUcE0T9F+uiJSwqJAESwqI8+aaK5EOuXTEOImmPHWMzD+NDmFbDbP8yqn6CMsKBnLopGeUwjuRAGw0KpPDegQA==@vger.kernel.org, AJvYcCWXiTOMdMez9LS7tJRmuMhucLzn4SocC69+ZFfny0eDSACezi7/bKsCQ3Jckxf7riUuigOazApTrrgZVJQ=@vger.kernel.org X-Gm-Message-State: AOJu0Yzi86y/AZ8YlylciIcyjgaIJHQFHgXuUCMPKGc+1nXcCWfrDOFG 9nDIgDfVN06txJL9qiJeMmgFFDTVzNdcm+kQTj+jTnMRo4K2k1xv X-Gm-Gg: ASbGncslcALG12OLZ1Z2DI1tvk4L3bpYnTMz5BDcazkVuIVzlSY/tOIRBqJKbHtOnFq J3Nb7Ly7qIAnLo1DgmwK287vLTnZF0L0YXLAl+YxRam0Ca4FHBNKXVFTSU6l+1ujTDa65bHrKTk 1YKWdtiywWsoKNizVXxRblH1SsGXtRZMIsGd3v2JnGxlh79EVZY1XF/s/aFNdjR3MO16oCDuhA3 ZV/xpEi2JLIcYeJuATZ4X9Vyz9cQt89EJqfzYlgjpIruTyUWrLS/cF7ngHIrZuYKjwSmqzCOCKK j7WuUwFqNA== X-Google-Smtp-Source: AGHT+IF51qhIkIR5re06wLikSJht5b6ND5XqzQnGpZlQfY0vJ266X8vE7+FjtkGUdwukKcQEX4lVxw== X-Received: by 2002:a17:90b:544b:b0:2ee:b2be:f390 with SMTP id 98e67ed59e1d1-2f13930a57bmr2137060a91.28.1733955935632; Wed, 11 Dec 2024 14:25:35 -0800 (PST) Received: from mbp.lan (c-73-202-46-50.hsd1.ca.comcast.net. [73.202.46.50]) by smtp.gmail.com with ESMTPSA id 98e67ed59e1d1-2ef6d1fd68asm11241561a91.36.2024.12.11.14.25.34 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 11 Dec 2024 14:25:35 -0800 (PST) From: Howard Chu To: acme@kernel.org Cc: namhyung@kernel.org, mark.rutland@arm.com, alexander.shishkin@linux.intel.com, jolsa@kernel.org, irogers@google.com, adrian.hunter@intel.com, kan.liang@linux.intel.com, linux-perf-users@vger.kernel.org, linux-kernel@vger.kernel.org, Howard Chu , Ingo Molnar , James Clark , Peter Zijlstra , Arnaldo Carvalho de Melo Subject: [PATCH v11 02/10] perf record --off-cpu: Parse off-cpu event Date: Wed, 11 Dec 2024 14:25:20 -0800 Message-ID: <20241211222528.945590-3-howardchu95@gmail.com> X-Mailer: git-send-email 2.43.0 In-Reply-To: <20241211222528.945590-1-howardchu95@gmail.com> References: <20241211222528.945590-1-howardchu95@gmail.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" Parse the off-cpu event using parse_event(), as bpf-output. no-inherit should be set to 1, here's the reason: We update the BPF perf_event map for direct off-cpu sample dumping (in following patches), it executes as follows: bpf_map_update_value() bpf_fd_array_map_update_elem() perf_event_fd_array_get_ptr() perf_event_read_local() In perf_event_read_local(), there is: int perf_event_read_local(struct perf_event *event, u64 *value, u64 *enabled, u64 *running) { ... /* * It must not be an event with inherit set, we cannot read * all child counters from atomic context. */ if (event->attr.inherit) { ret =3D -EOPNOTSUPP; goto out; } Which means no-inherit has to be true for updating the BPF perf_event map. Moreover, for bpf-output events, we primarily want a system-wide event instead of a per-task event. The reason is that in BPF's bpf_perf_event_output(), BPF uses the CPU index to retrieve the perf_event file descriptor it outputs to. Making a bpf-output event system-wide naturally satisfies this requirement by mapping CPU appropriately. Suggested-by: Namhyung Kim Reviewed-by: Ian Rogers Signed-off-by: Howard Chu Cc: Adrian Hunter Cc: Alexander Shishkin Cc: Ingo Molnar Cc: James Clark Cc: Jiri Olsa Cc: Kan Liang Cc: Mark Rutland Cc: Peter Zijlstra Link: https://lore.kernel.org/r/20241108204137.2444151-4-howardchu95@gmail.= com Signed-off-by: Arnaldo Carvalho de Melo --- tools/perf/util/bpf_off_cpu.c | 33 +++++++++++---------------------- tools/perf/util/evsel.c | 4 +++- 2 files changed, 14 insertions(+), 23 deletions(-) diff --git a/tools/perf/util/bpf_off_cpu.c b/tools/perf/util/bpf_off_cpu.c index a590a8ac1f9d..9275b022b2ea 100644 --- a/tools/perf/util/bpf_off_cpu.c +++ b/tools/perf/util/bpf_off_cpu.c @@ -38,32 +38,21 @@ union off_cpu_data { =20 static int off_cpu_config(struct evlist *evlist) { + char off_cpu_event[64]; struct evsel *evsel; - struct perf_event_attr attr =3D { - .type =3D PERF_TYPE_SOFTWARE, - .config =3D PERF_COUNT_SW_BPF_OUTPUT, - .size =3D sizeof(attr), /* to capture ABI version */ - }; - char *evname =3D strdup(OFFCPU_EVENT); - - if (evname =3D=3D NULL) - return -ENOMEM; =20 - evsel =3D evsel__new(&attr); - if (!evsel) { - free(evname); - return -ENOMEM; + scnprintf(off_cpu_event, sizeof(off_cpu_event), "bpf-output/name=3D%s/", = OFFCPU_EVENT); + if (parse_event(evlist, off_cpu_event)) { + pr_err("Failed to open off-cpu event\n"); + return -1; } =20 - evsel->core.attr.freq =3D 1; - evsel->core.attr.sample_period =3D 1; - /* off-cpu analysis depends on stack trace */ - evsel->core.attr.sample_type =3D PERF_SAMPLE_CALLCHAIN; - - evlist__add(evlist, evsel); - - free(evsel->name); - evsel->name =3D evname; + evlist__for_each_entry(evlist, evsel) { + if (evsel__is_offcpu_event(evsel)) { + evsel->core.system_wide =3D true; + break; + } + } =20 return 0; } diff --git a/tools/perf/util/evsel.c b/tools/perf/util/evsel.c index 867da727a486..d0f2d9e8ce6c 100644 --- a/tools/perf/util/evsel.c +++ b/tools/perf/util/evsel.c @@ -1521,8 +1521,10 @@ void evsel__config(struct evsel *evsel, struct recor= d_opts *opts, if (evsel__is_dummy_event(evsel)) evsel__reset_sample_bit(evsel, BRANCH_STACK); =20 - if (evsel__is_offcpu_event(evsel)) + if (evsel__is_offcpu_event(evsel)) { evsel->core.attr.sample_type &=3D OFFCPU_SAMPLE_TYPES; + attr->inherit =3D 0; + } =20 arch__post_evsel_config(evsel, attr); } --=20 2.43.0