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 E5355219E0; Mon, 23 Jun 2025 21:22:58 +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=1750713779; cv=none; b=b9h8U8rJoUt4VD+YuQFCDBnOEjH+dHnZQugCp1BiaGjY3yBSX7asRL+783WFs8a/Uwa7th5MYS41H3lZ3CXnJLYowUoCgaDW23XJZvI8pUMvQZrq9fC1syX8yK82LfWlNr0Un8AsxJSzwVTEJALRtzyxV6Kij5r4eooVzarluEo= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1750713779; c=relaxed/simple; bh=FIxI+W29N8/A/MWDBcJecy8Y6mRSR+3MQ4Kvfxcy8JI=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=pr7ToTOAn007Ur22qS8awdGy5q78dR+htfWdsfR9ElJreu7CEfiWC+ZKz8iR9ajYPbOgj4PX7jzn3ZVX5F0mENdEQWr//9Jp7ruYZRlaQWTPSI+4LMGmk7H7ITXd/brZNJCQoT5eEVopfnsHrvGNIUB2l872gilPSoMYs5+l5d8= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=QHggzuQw; 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="QHggzuQw" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 3625DC4CEEA; Mon, 23 Jun 2025 21:22:58 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1750713778; bh=FIxI+W29N8/A/MWDBcJecy8Y6mRSR+3MQ4Kvfxcy8JI=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=QHggzuQwBYwotcC0wa0zKk61zk6YIp+c7JGHTO+AiIOKKhFR2eqv9wh+imunpFpJz o4IBtpS4I4wizmWZAahS54+SyUAsbvGqpQK4qjCK2b7suBKWf2YVQdDt4URl1LlYP5 BfvXRx3XZJB+YkPcyWlUURTgiFpUDeVZf+8kf8U0= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Ian Rogers , Leo Yan , Adrian Hunter , James Clark , Kan Liang , Namhyung Kim , Arnaldo Carvalho de Melo , Sasha Levin Subject: [PATCH 6.1 146/508] perf tests switch-tracking: Fix timestamp comparison Date: Mon, 23 Jun 2025 15:03:11 +0200 Message-ID: <20250623130648.876740360@linuxfoundation.org> X-Mailer: git-send-email 2.50.0 In-Reply-To: <20250623130645.255320792@linuxfoundation.org> References: <20250623130645.255320792@linuxfoundation.org> User-Agent: quilt/0.68 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 6.1-stable review patch. If anyone has any objections, please let me know. ------------------ From: Leo Yan [ Upstream commit 628e124404b3db5e10e17228e680a2999018ab33 ] The test might fail on the Arm64 platform with the error: # perf test -vvv "Track with sched_switch" Missing sched_switch events # The issue is caused by incorrect handling of timestamp comparisons. The comparison result, a signed 64-bit value, was being directly cast to an int, leading to incorrect sorting for sched events. The case does not fail everytime, usually I can trigger the failure after run 20 ~ 30 times: # while true; do perf test "Track with sched_switch"; done 106: Track with sched_switch : Ok 106: Track with sched_switch : Ok 106: Track with sched_switch : Ok 106: Track with sched_switch : Ok 106: Track with sched_switch : Ok 106: Track with sched_switch : Ok 106: Track with sched_switch : Ok 106: Track with sched_switch : Ok 106: Track with sched_switch : Ok 106: Track with sched_switch : Ok 106: Track with sched_switch : Ok 106: Track with sched_switch : Ok 106: Track with sched_switch : Ok 106: Track with sched_switch : Ok 106: Track with sched_switch : FAILED! 106: Track with sched_switch : Ok 106: Track with sched_switch : Ok 106: Track with sched_switch : Ok 106: Track with sched_switch : Ok 106: Track with sched_switch : Ok 106: Track with sched_switch : Ok 106: Track with sched_switch : Ok 106: Track with sched_switch : Ok 106: Track with sched_switch : FAILED! 106: Track with sched_switch : Ok 106: Track with sched_switch : Ok I used cross compiler to build Perf tool on my host machine and tested on Debian / Juno board. Generally, I think this issue is not very specific to GCC versions. As both internal CI and my local env can reproduce the issue. My Host Build compiler: # aarch64-linux-gnu-gcc --version aarch64-linux-gnu-gcc (Ubuntu 13.3.0-6ubuntu2~24.04) 13.3.0 Juno Board: # lsb_release -a No LSB modules are available. Distributor ID: Debian Description: Debian GNU/Linux 12 (bookworm) Release: 12 Codename: bookworm Fix this by explicitly returning 0, 1, or -1 based on whether the result is zero, positive, or negative. Fixes: d44bc558297222d9 ("perf tests: Add a test for tracking with sched_switch") Reviewed-by: Ian Rogers Signed-off-by: Leo Yan Cc: Adrian Hunter Cc: James Clark Cc: Kan Liang Cc: Namhyung Kim Link: https://lore.kernel.org/r/20250331172759.115604-1-leo.yan@arm.com Signed-off-by: Arnaldo Carvalho de Melo Signed-off-by: Sasha Levin --- tools/perf/tests/switch-tracking.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/tools/perf/tests/switch-tracking.c b/tools/perf/tests/switch-tracking.c index 87f565c7f650d..db6c61424badf 100644 --- a/tools/perf/tests/switch-tracking.c +++ b/tools/perf/tests/switch-tracking.c @@ -257,7 +257,7 @@ static int compar(const void *a, const void *b) const struct event_node *nodeb = b; s64 cmp = nodea->event_time - nodeb->event_time; - return cmp; + return cmp < 0 ? -1 : (cmp > 0 ? 1 : 0); } static int process_events(struct evlist *evlist, -- 2.39.5