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 CD88F43E9D5 for ; Sun, 18 Oct 2026 08:31:08 +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=1792312269; cv=none; b=ZhGGNGHQ0hLI0VApgZwhFhmLpU11PxSGp4ss0K5Wnxfi4/DwCT14tq1ekUq406Cmnxde78rKyzIj4LiIrrh37o5IKBe2fbvxenWtekpMQ8Go6f4fmxYIW/vnuod56vPMZNBkggfRxA9XjEzIYxKx6NXItyABI/EzklGYarrWtu0= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1792312269; c=relaxed/simple; bh=OnjwOdyFr/cOymvd3pORVRdT0jy5PI6rARwOdCcoYVs=; h=Message-ID:From:Subject:To:Cc:In-Reply-To:References:Content-Type: Date; b=QtQgFcF/GwKSB/QQSAFl0SsWfdBWbmAc5z1YEeS9BqYsNqFDWnkBA0QGRW/spQwxRuucCryzvVCYHvzKUVS0Ved6FXUaazvBqg4HDyRDt4Q+oaVuZehHlzYLOBT2EkZ8po7Nhk3xQJQ98eEscY76QjEbtssPMk6J4tmS6AN1kU4= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=Ozb+sR3W; 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="Ozb+sR3W" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 6F1F81F000C4; Sun, 18 Oct 2026 08:31:08 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1792312268; bh=ssH0tpalLEEP1kG7RwNa7/8mMm6jtGSeO5X7J6DSHpA=; h=From:Subject:Reply-To:To:Cc:In-Reply-To:References:Date; b=Ozb+sR3WG/4CPKmfN0o6YLgUp4AIchB6MXaLxOQZNmqPN5s/yl7TtOocsu9YXMlcF nMkvtmyDkrMamqbcvPkZh6FsQ92AYcDyLnw75Sf/+Q4hpdtTi+VAlpe1MmleKaoH3z O+NdAGy3f7cnPiXBs5Is3pud4niB1SMijAUekf45aF7aCBjKM8iQT2w7brUfIDgAGO ivsjCwrbkLXgwMacAfsfgodcz3Iq6cojOPr5BDQAETjm4BLJR1xjnzF2P8h7xp3MFA UZ4iT98K8Nz0waF04JgvrVja6TqHeGQ1DiIB2jCzn4IsScaib1vXC3L0SX778fw37W z3NVyMNUHQ4Eg== Message-ID: From: sashiko-bot@kernel.org Subject: Re: [PATCH] perf python: Set up callchain parameters for sessions Reply-To: sashiko-reviews@lists.linux.dev To: "Lalit Maganti" Cc: linux-perf-users@vger.kernel.org In-Reply-To: <20261018081452.1014460-1-lalitmaganti@gmail.com> References: <20261018081452.1014460-1-lalitmaganti@gmail.com> Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable Date: Sun, 18 Oct 2026 08:31:08 +0000 Precedence: bulk X-Mailing-List: linux-perf-users@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: > perf.session never calls callchain_param_setup(), so callchains are > resolved with callchain_param.record_mode left as CALLCHAIN_NONE rather > than set from the sample type as in perf script and perf report. >=20 > On arm64 this loses frames: when a sample hits a function before it has > pushed its frame record, its caller is only in the link register, and > recovering it needs record_mode CALLCHAIN_FP. Comparing the callchain of > every sample with perf script, on a frame pointer recording of a > two-thread workload on arm64, 4 of 4494 samples miss a frame, e.g.: >=20 > perf script: clock_gettime@plt <- now <- spin <- other_path > perf.session: clock_gettime@plt <- spin <- other_path >=20 > Call callchain_param_setup() once the session is created and, as perf > script does, again as attrs are processed, for pipe mode. With that, > all callchains match perf script on arm64, for frame pointer and DWARF > recordings, from a file or a pipe. On x86 they matched before and still > do. >=20 > Assisted-by: LLM > Signed-off-by: Lalit Maganti Sashiko has reviewed this patch and found no issues. --=20 Sashiko AI review =C2=B7 https://sashiko.dev/#/patchset/20261018081452.1014= 460-1-lalitmaganti@gmail.com?part=3D1