From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id A71BE4C2251; Fri, 25 Sep 2026 15:07:22 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1790348862; cv=none; b=EYw905MCtNlQZWb37uyMYJLwEmMGwsNdbqgCtxI6cj9FIPcIb7IOwmwhWsM0b14boW4imnYGqcj/e5Hc4xcP437N8/y5vlK6vNfltxjalScFuBA+AxH+vRQ7ai+nj4AbHyFggP3CmGTu/+dHROR3jg+xwoyB0zL4XGXb1/7LHYQ= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1790348862; c=relaxed/simple; bh=eS2gsMBGKVP+FfEWA8fe2ToTtO8enH2bmmCgZy/cRPQ=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=sC+LfjrO3ys03KFfJXLIfslCbgzXdW+7ISGaRpo1H5cE3R1e977wCzd/5FYVq5qMWO8j+wxJMZ67OIXw4WkHPXlfg209ZujiRCvqUgbpF4Jp6axfjBpw4mVTuWmEmhUNHfOiI7oL8I7rW9QG4ccU52Z0eO/Xywo5ktEi1Sdg2Og= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=JYD+KN7u; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="JYD+KN7u" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 8D5841F0089B; Fri, 25 Sep 2026 15:07:14 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1790348836; bh=9mYogseKBX+5WWtCwyglsgqeN/PRVM6Ugb0klUJ5z6Y=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=JYD+KN7uBoEDBGgr8KXCSxsYvy4iHMs+RWdA1xuih0QVQ22/IkO+DZdX8+gOMpE4w kfd7blqKbmoLc9hgeho1J0034cgMIzm3NThRtcKDT57NjsoiT/agx9LtSeFLo3hZ3x XmCVoruP45loKqT1OXVWPWHiZ++mHlUcmBfnlAFmsqwXI+2ZWQPkTdIuk8PkxphZPm 8IMiYmLph3P/p6uCBFtvvrjjiIMiPw7Eu14m8225UM5S7NcidhC7f+2qNrOMbk/xpB 8kI5vO6haIkUqWjeGp31WRRMDzkbCAqT40/gzXdxDihgHMeklwARIS5L6IH3nuICGF VArUBYuqbuXoA== From: Arnaldo Carvalho de Melo To: Namhyung Kim Cc: Ingo Molnar , Thomas Gleixner , James Clark , Jiri Olsa , Ian Rogers , Adrian Hunter , Clark Williams , linux-kernel@vger.kernel.org, linux-perf-users@vger.kernel.org, Arnaldo Carvalho de Melo Subject: [PATCH 5/6] perf mem record: Request PERF_SAMPLE_CPU by default Date: Fri, 25 Sep 2026 17:06:56 +0200 Message-ID: <20260925150657.1826942-6-acme@kernel.org> X-Mailer: git-send-email 2.55.0 In-Reply-To: <20260925150657.1826942-1-acme@kernel.org> References: <20260925150657.1826942-1-acme@kernel.org> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit From: Arnaldo Carvalho de Melo The data type profiling per-sample stream keys cross-CPU contention on sample->cpu, which without PERF_SAMPLE_CPU is the "no CPU info" sentinel, making same-instance accesses from different cores indistinguishable from same-CPU traffic. 'perf mem record' already passes -d and -W to the record parser, add --sample-cpu and document it in perf-mem(1). Also grow rec_argv: the new entry overflows it on PMUs with separate load and store events, as the space for the fixed arguments was not reserved. Assisted-by: LLM Signed-off-by: Arnaldo Carvalho de Melo --- tools/perf/Documentation/perf-mem.txt | 4 ++++ tools/perf/builtin-mem.c | 7 +++++-- 2 files changed, 9 insertions(+), 2 deletions(-) diff --git a/tools/perf/Documentation/perf-mem.txt b/tools/perf/Documentation/perf-mem.txt index 4d164836d0943119..fe51c5e3333dc4a0 100644 --- a/tools/perf/Documentation/perf-mem.txt +++ b/tools/perf/Documentation/perf-mem.txt @@ -14,6 +14,10 @@ DESCRIPTION ----------- "perf mem record" runs a command and gathers memory operation data from it, into perf.data. Perf record options are accepted and are passed through. +It also requests the address (-d), the weight (-W, where supported) and the +CPU id (--sample-cpu) of every sampled access by default; the CPU id is what +lets per-sample analysis tell reads and writes to the same data from +different cores apart from same-CPU traffic. "perf mem report" displays the result. It invokes perf report with the right set of options to display a memory access profile. By default, loads diff --git a/tools/perf/builtin-mem.c b/tools/perf/builtin-mem.c index 6101a26b3a781e69..ade53688ebcd0f10 100644 --- a/tools/perf/builtin-mem.c +++ b/tools/perf/builtin-mem.c @@ -99,8 +99,8 @@ static int __cmd_record(int argc, const char **argv, struct perf_mem *mem, argc = parse_options(argc, argv, options, record_usage, PARSE_OPT_KEEP_UNKNOWN); - /* Max number of arguments multiplied by number of PMUs that can support them. */ - rec_argc = argc + 9 * (perf_pmu__mem_events_num_mem_pmus(pmu) + 1); + /* Max number of arguments per PMU plus the fixed ones added below. */ + rec_argc = argc + 8 + 9 * (perf_pmu__mem_events_num_mem_pmus(pmu) + 1); if (mem->cpu_list) rec_argc += 2; @@ -135,6 +135,9 @@ static int __cmd_record(int argc, const char **argv, struct perf_mem *mem, rec_argv[i++] = "-d"; + /* Cross-CPU contention keys on sample->cpu, -1 without PERF_SAMPLE_CPU. */ + rec_argv[i++] = "--sample-cpu"; + if (mem->phys_addr) rec_argv[i++] = "--phys-data"; -- 2.53.0