[LTP] [PATCH 2/2] syscalls: Add timer measurement library

[Cyril Hrubis]

Hi!
> > Hi,
> > 
> > looks good to me.

Pushed with your ack.

> > It compiled fine across RHEL 5/6/7 x86_64. No failures when I run it
> > on my laptop.
> > 
> > I plan to also run it across multiple arches/distros on randomly
> > picked systems from lab.
> 
> Results from ~35 random RHEL6/7 systems look OK. I've hit
> one failure in RHEL6, but that looks like bug in older kernel,
> because the delays are huge:
> 
> tst_test.c:870: INFO: Timeout per run is 0h 05m 00s
> tst_timer_test.c:345: INFO: CLOCK_MONOTONIC resolution 1ns
> tst_timer_test.c:357: INFO: prctl(PR_GET_TIMERSLACK) = 50us
> tst_timer_test.c:275: INFO: nanosleep() sleeping for 1000us 500 iterations, threshold 450.01us
> tst_timer_test.c:296: INFO: Found 488 outliners in [500430,12493] range
> tst_timer_test.c:318: INFO: min 1056us, max 500430us, median 500198us, trunc mean 466362.70us (discarded 25)
> tst_timer_test.c:321: FAIL: nanosleep() slept for too long
> 
>  Time: us | Frequency
> --------------------------------------------------------------------------------
>      1056 | **+
>     27339 | -
>     53622 | -
>     79905 | .
>    106188 | -
>    132471 | .
>    158754 | .
>    185037 | -
>    211320 | .
>    237603 | -
>    263886 | .
>    290169 | -
>    316452 | .
>    342735 | -
>    369018 | -
>    395301 | .
>    421584 | -
>    447867 | -
>    474150 | ********************************************************************
> --------------------------------------------------------------------------------
>   26283us | 1 sample = 0.15044 '*', 0.30088 '+', 0.60177 '-', non-zero '.'
> 
> Not reproducible when I try to run it by hand.

That indeed looks like a kernel bug, isn't there something in dmesg?

-- 
Cyril Hrubis
chrubis@suse.cz