From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (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 8F4A71D0B99; Wed, 2 Oct 2024 14:37:17 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1727879837; cv=none; b=ZRtqwW96k0weNbnPSain9YD0JBm6yn98YfhBCUWFSko8uBxsmEFqzi9kaKjQ6wd/SwvttJOhWMIfGaJeodcI/7vjqhJzSblGe3+G/fnZ6W6VJenOyRYWGBjs1aVp2GBgj9tZ5cReHOvugYprA+x3JsPjgxiEKU6iKASmG82hz4s= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1727879837; c=relaxed/simple; bh=ZTj4a74VmxmBlFmSLE6t2dTMkRM+y7mY+NIzzMSb+Iw=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=RsvMjODLjzYXNJsRfE2onTCQpNcxJQMfXZEF18Z2anV2nj7+MhNfq7pUW/q9j2DAiMC81iaBR/+7I/aB1/kvi5rJC8k+iromgwyi5ws/GXqjRTbXbt0krMofwab7Z6rW9izLajhE2/rp56b1OszXFLSqZQ0p3okkUlw5EMDjKMo= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=tzuPaIa7; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="tzuPaIa7" Received: by smtp.kernel.org (Postfix) with ESMTPSA id DCDADC4CEC2; Wed, 2 Oct 2024 14:37:16 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1727879837; bh=ZTj4a74VmxmBlFmSLE6t2dTMkRM+y7mY+NIzzMSb+Iw=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=tzuPaIa7NkuKZM70wp23MNrsn9Yw+YlaHXvIkllBOMmJFUJwVv3iQDbmeW0lHCERl 0/0yZLJE8XiHoHtuarl6EeQY56dHcNueDzQ8PpjvRUps6+6BJAs9ZyseGH5poIRf6z TVU2dyuR/IfUtHrP5Z0kzrvB1/VRTwUfmu39DuUw= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Yang Jihong , Namhyung Kim , Adrian Hunter , Alexander Shishkin , David Ahern , Ian Rogers , Ingo Molnar , James Clark , Jiri Olsa , Kan Liang , Mark Rutland , Peter Zijlstra , Arnaldo Carvalho de Melo , Sasha Levin Subject: [PATCH 6.6 255/538] perf sched timehist: Fixed timestamp error when unable to confirm event sched_in time Date: Wed, 2 Oct 2024 14:58:14 +0200 Message-ID: <20241002125802.323179149@linuxfoundation.org> X-Mailer: git-send-email 2.46.2 In-Reply-To: <20241002125751.964700919@linuxfoundation.org> References: <20241002125751.964700919@linuxfoundation.org> User-Agent: quilt/0.67 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 6.6-stable review patch. If anyone has any objections, please let me know. ------------------ From: Yang Jihong [ Upstream commit 39c243411bdb8fb35777adf49ee32549633c4e12 ] If sched_in event for current task is not recorded, sched_in timestamp will be set to end_time of time window interest, causing an error in timestamp show. In this case, we choose to ignore this event. Test scenario: perf[1229608] does not record the first sched_in event, run time and sch delay are both 0 # perf sched timehist Samples of sched_switch event do not have callchains. time cpu task name wait time sch delay run time [tid/pid] (msec) (msec) (msec) --------------- ------ ------------------------------ --------- --------- --------- 2090450.763231 [0000] perf[1229608] 0.000 0.000 0.000 2090450.763235 [0000] migration/0[15] 0.000 0.001 0.003 2090450.763263 [0001] perf[1229608] 0.000 0.000 0.000 2090450.763268 [0001] migration/1[21] 0.000 0.001 0.004 2090450.763302 [0002] perf[1229608] 0.000 0.000 0.000 2090450.763309 [0002] migration/2[27] 0.000 0.001 0.007 2090450.763338 [0003] perf[1229608] 0.000 0.000 0.000 2090450.763343 [0003] migration/3[33] 0.000 0.001 0.004 Before: arbitrarily specify a time window of interest, timestamp will be set to an incorrect value # perf sched timehist --time 100,200 Samples of sched_switch event do not have callchains. time cpu task name wait time sch delay run time [tid/pid] (msec) (msec) (msec) --------------- ------ ------------------------------ --------- --------- --------- 200.000000 [0000] perf[1229608] 0.000 0.000 0.000 200.000000 [0001] perf[1229608] 0.000 0.000 0.000 200.000000 [0002] perf[1229608] 0.000 0.000 0.000 200.000000 [0003] perf[1229608] 0.000 0.000 0.000 200.000000 [0004] perf[1229608] 0.000 0.000 0.000 200.000000 [0005] perf[1229608] 0.000 0.000 0.000 200.000000 [0006] perf[1229608] 0.000 0.000 0.000 200.000000 [0007] perf[1229608] 0.000 0.000 0.000 After: # perf sched timehist --time 100,200 Samples of sched_switch event do not have callchains. time cpu task name wait time sch delay run time [tid/pid] (msec) (msec) (msec) --------------- ------ ------------------------------ --------- --------- --------- Fixes: 853b74071110bed3 ("perf sched timehist: Add option to specify time window of interest") Signed-off-by: Yang Jihong Acked-by: Namhyung Kim Cc: Adrian Hunter Cc: Alexander Shishkin Cc: David Ahern Cc: Ian Rogers Cc: Ingo Molnar Cc: James Clark Cc: Jiri Olsa Cc: Kan Liang Cc: Mark Rutland Cc: Peter Zijlstra Link: https://lore.kernel.org/r/20240819024720.2405244-1-yangjihong@bytedance.com Signed-off-by: Arnaldo Carvalho de Melo Signed-off-by: Sasha Levin --- tools/perf/builtin-sched.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) diff --git a/tools/perf/builtin-sched.c b/tools/perf/builtin-sched.c index 489a5ef2a25de..42185da0f000a 100644 --- a/tools/perf/builtin-sched.c +++ b/tools/perf/builtin-sched.c @@ -2633,9 +2633,12 @@ static int timehist_sched_change_event(struct perf_tool *tool, * - previous sched event is out of window - we are done * - sample time is beyond window user cares about - reset it * to close out stats for time window interest + * - If tprev is 0, that is, sched_in event for current task is + * not recorded, cannot determine whether sched_in event is + * within time window interest - ignore it */ if (ptime->end) { - if (tprev > ptime->end) + if (!tprev || tprev > ptime->end) goto out; if (t > ptime->end) -- 2.43.0