Messages in this thread | | | Date | Tue, 31 Mar 2015 10:01:44 -0600 | From | Shuah Khan <> | Subject | Re: [PATCH 2/2] kselftests: timers: Reduce default runtime on inconsistency-check and set-timer-lat |
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On 03/26/2015 10:20 AM, John Stultz wrote: > On Thu, Mar 26, 2015 at 4:32 AM, Prarit Bhargava <prarit@redhat.com> 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 <shuahkh@osg.samsung.com> >>> Cc: Prarit Bhargava <prarit@redhat.com> >>> Cc: Thomas Gleixner <tglx@linutronix.de> >>> Cc: Richard Cochran <richardcochran@gmail.com> >>> Signed-off-by: John Stultz <john.stultz@linaro.org> >>> Signed-off-by: John Stultz <john.stultz@linaro.org>
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
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