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 0ED1A385D99 for ; Sun, 13 Sep 2026 03:42:08 +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=1789270930; cv=none; b=Sa+SyPeDG0giLEc/x3Rz+BXCUVRSLt2urFOTJD1YnhCTl0CET489c1j9YpUFntDe3yx1enOm6psKN95gTzH+eVOzGRTuLkLJf8qjLvfm5KF3rYLqnmTK8u2RZg73WkV8lMxhAiYtmYW3oPC5nLLZuPK9c879LzpI2vEdegfS90w= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1789270930; c=relaxed/simple; bh=1b88AB6i3CGp2vl6Kj7kAo9WtJU6xixPWCDRjPcwLag=; h=From:Subject:To:Cc:In-Reply-To:References:Content-Type:Date: Message-Id; b=jZThpp8ER4FvjfilTMdZ2OwHU7mLrBiyhKNj/O9aHiloAmcaUZUZsYdsmtzZcXnqzzo48yojv3kEuR5ZSrTnvQpzge+nqEKTMG8b+FBCLCIOI/nAdLIWO9P08DdNS2VJ0szNpCJXVGZUIJhVVHqk+Rd4IWLrktt8kg/5wb59UyI= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=d7YwZkZL; 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="d7YwZkZL" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 7B0F21F00893; Sun, 13 Sep 2026 03:42:08 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1789270928; bh=1b88AB6i3CGp2vl6Kj7kAo9WtJU6xixPWCDRjPcwLag=; h=From:Subject:Reply-To:To:Cc:In-Reply-To:References:Date; b=d7YwZkZL/9sMnFEDn1xqtg27/+M7+w9/H5qqMxC+w6DRBIp4oEA+O9jp2HsFzfaCH na/QVVYC0CxSMZV3TuTyzpvINs4bQMOqX6YxzbJvxaQGBYBmR9NlacgUQpC2H3IRNN BanpjTmhsghTOw0ssQKtiGlzbB5KTiPWByTCs5oDvSOh5oaCUqui3KNPwEKSKlaZce 1Lhr/Ejgph/OJKbGi9/8NtrCN7FnHtTIHDT4+kXhm3FrfmoXiztFEK9uZ3fUcDlWFq 00pJIOHb7BsMZi7laB+4E4wRnOz8lI5s0u4g4emWoSa+FFPAodZMT/HJUhrA9bXgJ+ DVjT8yF2uo/HA== From: sashiko-bot@kernel.org Subject: Re: [PATCH v2 8/8] perf mem record: Request PERF_SAMPLE_CPU by default Reply-To: sashiko-reviews@lists.linux.dev To: "Arnaldo Carvalho de Melo" Cc: linux-perf-users@vger.kernel.org In-Reply-To: <20260913032632.116277-9-acme@kernel.org> References: <20260913032632.116277-1-acme@kernel.org> <20260913032632.116277-9-acme@kernel.org> Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable Date: Sun, 13 Sep 2026 03:42:08 +0000 Message-Id: <20260913034208.7B0F21F00893@smtp.kernel.org> Precedence: bulk X-Mailing-List: linux-perf-users@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: > From: Arnaldo Carvalho de Melo >=20 > The data-type profiling per-sample stream keys cross-CPU contention on > sample->cpu: without PERF_SAMPLE_CPU the cpu field is the (u32)-1 "no > CPU info" sentinel, documented as such in perf_session__deliver_event(), > and same-instance reads and writes from different cores are > indistinguishable from same-CPU traffic, so pahole's false-sharing > detector cannot tell them apart. >=20 > builtin-record.c already defines --sample-cpu and 'perf mem record' > forwards unknown options to the record parser, so passing it explicitly > works today; make it the default, next to the -d (addr) and -W (weight) > the command already requests, documenting it in perf-mem(1). >=20 > Assisted-by: LLM > Signed-off-by: Arnaldo Carvalho de Melo Sashiko has reviewed this patch and found no issues. It looks great! --=20 Sashiko AI review =C2=B7 https://sashiko.dev/#/patchset/20260913032632.1162= 77-1-acme@kernel.org?part=3D8