From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by smtp.subspace.kernel.org (Postfix) with ESMTP id 959CF19BA6; Wed, 10 Apr 2024 09:07:30 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=217.140.110.172 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1712740053; cv=none; b=K+p90tKzVV+pSdWEXvshyya9F38v5dE25JFf4aEtAq67BI8YoPTrgg1U2bxWzZdTYIBIZhdtxt0fUXzenfmtvd1WCWlU4PK88h08fom2+2r6qk5JSbuHukUIPPXqW8ti17/clztQx2bHyabswvfZqz4kUSaa4U9eiyMvfFhZEYY= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1712740053; c=relaxed/simple; bh=DCFRPg6qIxiB1ACreiHrvx9LkKXCawxI0vGuJQNuNrs=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=VH0Z5pizymuyzUOGKRZpCSeX8j4lo7TyB47NormIdBzBvEsuk51VCrM2lkXT88KakRaKC953WFjhaYKlSGplGScIHaWXxz4K2ZXRXBV5ymFu5p+6IZLRXldV9c5No8BlNDbGXvpLhzWPG2Absh+B/UeUzKEudfnoM6Pe9RuPmHU= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=arm.com; spf=pass smtp.mailfrom=arm.com; arc=none smtp.client-ip=217.140.110.172 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=arm.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=arm.com Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 98140139F; Wed, 10 Apr 2024 02:07:59 -0700 (PDT) Received: from [192.168.1.100] (unknown [172.31.20.19]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id ED0143F6C4; Wed, 10 Apr 2024 02:07:27 -0700 (PDT) Message-ID: <8d776c30-0e5c-4caf-9b7e-52adb6115eab@arm.com> Date: Wed, 10 Apr 2024 10:07:26 +0100 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH 3/3] perf tests: Skip "test data symbol" on Neoverse N1 To: Namhyung Kim , Ian Rogers Cc: linux-perf-users@vger.kernel.org, Peter Zijlstra , Ingo Molnar , Arnaldo Carvalho de Melo , Mark Rutland , Alexander Shishkin , Jiri Olsa , Adrian Hunter , "Liang, Kan" , Athira Rajeev , Leo Yan , linux-kernel@vger.kernel.org References: <20240409084741.405433-1-james.clark@arm.com> <20240409084741.405433-4-james.clark@arm.com> Content-Language: en-US From: James Clark In-Reply-To: Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit On 10/04/2024 00:17, Namhyung Kim wrote: > Hi Ian and James, > > On Tue, Apr 9, 2024 at 8:39 AM Ian Rogers wrote: >> >> On Tue, Apr 9, 2024 at 1:48 AM James Clark wrote: >>> >>> To prevent anyone from seeing a test failure appear as a regression and >>> thinking that it was caused by their code change, just skip the test on >>> N1. >>> >>> It can be caused by any unrelated change that shifts the loop into an >>> unfortunate position in the Perf binary which is almost impossible to >>> debug as the root cause of the test failure. Ultimately it's caused by >>> the referenced errata. >>> >>> Fixes: 60abedb8aa90 ("perf test: Introduce script for data symbol testing") >>> Signed-off-by: James Clark >> >> This change makes me sad :-( Is there no hope of aligning the loop? We >> have little enough testing coverage for memory events and even precise >> events on ARM that anything take away testing coverage feels like we >> should try to do better. > > Can we just add some noise in the loop? > > Thanks, > Namhyung > Yes that would probably work. I decided to skip rather than touch the test because I didn't want the errata on one specific core to affect testing everywhere else. But if we don't think that it's too hacky to include that in the test then I can add it. To be honest maybe it makes the test more "realistic" because a very short infinite loop doesn't really represent a real workload. > > diff --git a/tools/perf/tests/workloads/datasym.c > b/tools/perf/tests/workloads/datasym.c > index ddd40bc63448..e2514bf393cd 100644 > --- a/tools/perf/tests/workloads/datasym.c > +++ b/tools/perf/tests/workloads/datasym.c > @@ -16,6 +16,8 @@ static int datasym(int argc __maybe_unused, const > char **argv __maybe_unused) > { > for (;;) { > buf1.data1++; > + if ((buf1.data1 % 100129) == 0) > + buf1.data1++; > buf1.data2 += buf1.data1; > } > return 0; >