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 131363EDE54 for ; Mon, 17 Aug 2026 22:41:03 +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=1787006464; cv=none; b=tsuWwcuT10Nb5KWmaC5szF5t7tKbtuNsXxpjHeRtwru02ZniAbTFb2IaT4DfTUvD8Bgj/RmTCPFX5/4SrQL2e9uksicuzJJ/tQMG34YN+wDO8YuwUNm4o8wMoDVeEyOxKWOkkMldrlysXAKWpggqRtgrQiIhWlEwZ32QvmHU1AE= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1787006464; c=relaxed/simple; bh=i1fwicbj8mdkdbOK0MNOl93FAKIck9AN6eK7KEPFC2Y=; h=From:Subject:To:Cc:In-Reply-To:References:Content-Type:Date: Message-Id; b=ELhytR7GDwBc97HrcFS0st13qtRL/ScEw//aWb78fjrUpyRR1bsFZeUSzcmEnOs6WCYZjWN09ORAqMjESuNvLAj63TqLYQL7yM0i/eDe2Shh4tn9apVoN3Ivmq9bYvm2TXqr/WdFEmfG005muTibEppEiQ8OcP3X4L4n4uS83I8= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=VzM4Vs6Q; 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="VzM4Vs6Q" Received: by smtp.kernel.org (Postfix) with ESMTPSA id C97E41F000E9; Mon, 17 Aug 2026 22:41:02 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1787006463; bh=i1fwicbj8mdkdbOK0MNOl93FAKIck9AN6eK7KEPFC2Y=; h=From:Subject:Reply-To:To:Cc:In-Reply-To:References:Date; b=VzM4Vs6QJf61A0t1Bt9CDcFMAaTDUYtxWVvd0ju4B/smNhUylIzjwU/2Zv+jCPP2R 5VCdLwpsSThzQf5uH1FdcIZGIUELPtFs6vZbMXwTQVRCgDFEpkICCxMkjiDWMHMDD9 amvyk3ZafdAE+RdV34IpOGYI6x/pKgJSsQU7ECVIvZ6EE0GHjDxyYSRiXlkGLGsz6H flR7Edb6b1M5np2gpYaLIIKXrsdFJVOtRG8TBTFSpGKqmW69zBL0Rq0aLN2MK6BA1n D2kiTe6A8wQ0KAFO2iM/adDQtk5hSqDqiBaMMP00rumqF05q0I5YGjKtT/FPiC85Z8 HSVL4PbfUbEdA== From: sashiko-bot@kernel.org Subject: Re: [PATCH v2 3/5] perf cs-etm: Add branch history to existing samples Reply-To: sashiko-reviews@lists.linux.dev To: "Amir Ayupov" Cc: linux-perf-users@vger.kernel.org In-Reply-To: <454bc49f51eeef9f758fc2d2c7af75889d8aff46.1787005265.git.aaupov@fb.com> References: <454bc49f51eeef9f758fc2d2c7af75889d8aff46.1787005265.git.aaupov@fb.com> Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable Date: Mon, 17 Aug 2026 22:41:02 +0000 Message-Id: <20260817224102.C97E41F000E9@smtp.kernel.org> Precedence: bulk X-Mailing-List: linux-perf-users@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: > Implement --itrace=3DL for CoreSight ETM: decode timestamped trace up to > each existing PMU sample and attach the branch history that led to it. > The sample keeps its own ip, callchain and event identity, and a sample > that already carries a branch stack is left alone. >=20 > Samples are correlated with the trace by time, so this requires virtual > ETM timestamps that are correlated to perf time; timeless decoding is > rejected. The decode loop, which the previous patch left on its own in > cs_etm__process_timestamped_queues(), grows a timestamp argument and > stops once the decode frontier reaches it, so on return the > thread stack holds the branches that executed before the sample and none > that executed after. Attaching then reduces to the same > thread_stack__br_sample_late() call intel-pt uses. >=20 > No explicit sample-to-queue matching is needed: > [ ... ] > can actually return n entries. Kernel-inclusive trace gets the same > conservative 1024-entry headroom that intel-pt uses. >=20 > Assisted-by: Devmate:GPT-5.6 > Signed-off-by: Amir Ayupov Sashiko has reviewed this patch and found no issues. It looks great! --=20 Sashiko AI review =C2=B7 https://sashiko.dev/#/patchset/cover.1787005265.gi= t.aaupov@fb.com?part=3D3