From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753868AbbCaQBt (ORCPT ); Tue, 31 Mar 2015 12:01:49 -0400 Received: from lists.s-osg.org ([54.187.51.154]:55762 "EHLO lists.s-osg.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753722AbbCaQBq (ORCPT ); Tue, 31 Mar 2015 12:01:46 -0400 Message-ID: <551AC4E8.7090309@osg.samsung.com> Date: Tue, 31 Mar 2015 10:01:44 -0600 From: Shuah Khan Organization: Samsung Open Source Group User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:31.0) Gecko/20100101 Thunderbird/31.5.0 MIME-Version: 1.0 To: John Stultz , Prarit Bhargava CC: lkml , Thomas Gleixner , Richard Cochran Subject: Re: [PATCH 2/2] kselftests: timers: Reduce default runtime on inconsistency-check and set-timer-lat References: <1427327073-19011-1-git-send-email-john.stultz@linaro.org> <1427327073-19011-2-git-send-email-john.stultz@linaro.org> <5513EE54.5090203@redhat.com> In-Reply-To: Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 03/26/2015 10:20 AM, John Stultz wrote: > On Thu, Mar 26, 2015 at 4:32 AM, Prarit Bhargava wrote: >> On 03/25/2015 07:44 PM, John Stultz wrote: >>> For the default run_timers target, the timers tests takes the >>> majority of kselftests runtime. >>> >>> So this patch reduces the default runtime for inconsistentcy-check >>> and set-timer-lat, which reduced the runtime almost in half. >>> >>> Before: 11m48.629s >>> After: 6m47.723s >>> >>> Cc: Shuah Khan >>> Cc: Prarit Bhargava >>> Cc: Thomas Gleixner >>> Cc: Richard Cochran >>> Signed-off-by: John Stultz >>> Signed-off-by: John Stultz Same duplicate signature warning on this, no need to re-send. I will fix it when I apply the patch. -- Shuah >>> --- >>> tools/testing/selftests/timers/inconsistency-check.c | 2 +- >>> tools/testing/selftests/timers/set-timer-lat.c | 2 +- >>> 2 files changed, 2 insertions(+), 2 deletions(-) >>> >>> diff --git a/tools/testing/selftests/timers/inconsistency-check.c b/tools/testing/selftests/timers/inconsistency-check.c >>> index 578e423a..caf1bc9 100644 >>> --- a/tools/testing/selftests/timers/inconsistency-check.c >>> +++ b/tools/testing/selftests/timers/inconsistency-check.c >>> @@ -166,7 +166,7 @@ int main(int argc, char *argv[]) >>> int clockid, opt; >>> int userclock = CLOCK_REALTIME; >>> int maxclocks = NR_CLOCKIDS; >>> - int runtime = 30; >>> + int runtime = 10; >>> struct timespec ts; >>> >> >> Oops ... left everyone off :) >> >> What was the reason that this was originally 30? Or was that overkill? > > So time inconsistencies (when they manifest, which ideally is never) > can be fairly rare events. In the past we've seen them due to cpu TSC > skew and drift, which requires enough scheduler noise to pop the > process around between cores enough to notice, and enough system > runtime for the TSCs to drift far enough apart.. Or we've had tiny > accumulation bugs in update_wall_time which requires the right phase > in the error accumulation to align with an irq. So the consistency > test has always been a long running test (originally I'd run it > overnight), and the 30sec interval here was added just so there was > some "long enough" interval that wasn't too painful for me to test > submitted patches with. Now that more folks are using it (and they > likely care less), we can cut it down further to avoid making test > runs too onerous. > > Now, a patch might badly break things and it would be immediately > obvious to the test that something is wrong, so a quick check isn't > worthless, but it just doesn't instill that much confidence from me. > > I think as the kselftests grow, we'll have more "types" of test > targets to run (quick, long, stress, etc), and we can scale the time > in those tests accordingly. But the default should probably lean > towards the short side. > Right. I am working on adding support for quick, long etc. The goal for quick (default) mode is to complete the test runs in 15-20 minutes to make it easier for developers make it part of the work-flow. thanks, -- Shuah -- Shuah Khan Sr. Linux Kernel Developer Open Source Innovation Group Samsung Research America (Silicon Valley) shuahkh@osg.samsung.com | (970) 217-8978