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 2C5B128369F; Wed, 28 May 2025 13:08:56 +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=1748437737; cv=none; b=lQ4KZs8O3ptj1ct36tj4ROOQf682PD86cUSsclEL2e1jB/fxSdRO2FzQiKsDmBD1fMjIK6/R4fGS4A5SZbJjkfx3Sx6qxD/n6KRQoTrpyqwFhsnd/5qF/0UvnYhYIcd2a9RaoLO4VvuWtDaESb01Z1g5SgcEKvtMgO21sFd6GWk= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1748437737; c=relaxed/simple; bh=Mk5F2XnA3g8hN7duqFGxmuou7OdhCtgoPWCpS5amOi8=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=vGJn+H2HvtYFJkZ6/ytZ1Qa/+nachhziUJ05vhJQF91rkUFvgAWE5bKqYV5x0mwZn8kMTjkryxcN5b9pidtiM63IINs70Y2PPzRRSJ9Hg3fZBRcftqcRV7SI2BUg01avMzY2MalOT0VRnze2l0BuGtKJ6AdyjA3bLFOQ4evAB/4= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=Np/WK2Ga; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="Np/WK2Ga" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 143D5C4CEE7; Wed, 28 May 2025 13:08:55 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1748437736; bh=Mk5F2XnA3g8hN7duqFGxmuou7OdhCtgoPWCpS5amOi8=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=Np/WK2GabatE2gne2mHHy4kvHMSkTY5j9zZW/VAFLl5C8mOQIBcZGfgdrkdVt4DI9 akDQqxkSnZvD8qEg/4i4P5w/B3uk4xXgDuE35ML1BL+TCD/rQb98JapJKaoMsiwHu4 7Q20Rw/ilgKfg/kds48n+6mBq7in2AOCKkChq0LoTkwbmGtdQ+KOuT20jvu1lD4OMr 9BJ/wyWuhoHwjIHdUQ91HPlGrhJu5s7Mr6FgIt01rIALediM07eAuP5NYJPXWMOjnL HNHE/5wMfsIOuswUJIImO1b3YggxEd/KjU7O2msmrw7iCLJXf14scVavqoc8mh2Fxm s/ClZMgtHWDaA== Date: Wed, 28 May 2025 10:08:53 -0300 From: Arnaldo Carvalho de Melo To: Leo Yan Cc: Namhyung Kim , Ian Rogers , Adrian Hunter , "Liang, Kan" , James Clark , linux-perf-users@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH] perf tests switch-tracking: Fix timestamp comparison Message-ID: References: <20250331172759.115604-1-leo.yan@arm.com> <20250523081036.GB2566836@e132581.arm.com> <20250527094924.GF2566836@e132581.arm.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20250527094924.GF2566836@e132581.arm.com> On Tue, May 27, 2025 at 10:49:24AM +0100, Leo Yan wrote: > On Fri, May 23, 2025 at 02:12:58PM -0300, Arnaldo Carvalho de Melo wrote: > [...] > > Thanks for the extra info, I'll add it to the commit log message, and > > perhaps we could make this test exclusive and use stress-ng to generate > > some background noise in the form of a good number of processes, see: > > root@x1:~# stress-ng --switch $(($(nproc) * 2)) --timeout 30s & for a in $(seq 50) ; do perf test switch ; done > Thanks for sharing the test command. > > > Now with your patch it also fails, so its for another reason: > > --- start --- > > test child forked, pid 1777071 > > Using CPUID GenuineIntel-6-BA-3 > > mmap size 528384B > > 45221 events recorded > > Missing comm events > > ---- end(-1) ---- > > 113: Track with sched_switch : FAILED! > > > > Lots of short lived processes makes it fail as well :-\ > I searched internal CI record, we also occasionally saw the error: > Missing cycles events > I will find time to check if anything in test can be improved. Seems > to me, the test is fragile if system has background activities. Great! > > Your patch is correct, so I'll probably just add your comments and go > > with it. > Thanks! Also thanks Ian's suggestion for the iteration command. You're welcome, thanks for your work on improving perf, really appreciated! - Arnaldo