[LTP] [PATCH] tst_timer: fix verification of execution time

[Cyril Hrubis]

Hi!
> Each sample needs to be in range:
>     t < s[i] < t + threshold
> Thus for i from the interval [d...n]:
>     (n-d)*t < sum(s[d...n]) < (n-d)*(t + threshold)
> This patch fixes that check.

As far as I can tell the function compute_treshold() multiplies the
threshold per call by keep_samples already, so it's a threashold per run
not a treshold per call, or do I miss something?

> Signed-off-by: Piotr Gawel <piotr.krzysztof.gawel@gmail.com>
> ---
>  lib/tst_timer_test.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/lib/tst_timer_test.c b/lib/tst_timer_test.c
> index f6459e5..4508e29 100644
> --- a/lib/tst_timer_test.c
> +++ b/lib/tst_timer_test.c
> @@ -306,7 +306,7 @@ void do_timer_test(long long usec, unsigned int nsamples)
>  		samples[nsamples-1], samples[0], median,
>  		1.00 * trunc_mean / keep_samples, discard);
>  
> -	if (trunc_mean > (nsamples - discard) * usec + threshold) {
> +	if (trunc_mean > keep_samples * (usec + threshold)) {
>  		tst_res(TFAIL, "%s slept for too long", scall);
>  		if (!print_frequency_plot)
> -- 
> 2.7.4
> 
> 
> -- 
> Mailing list info: https://lists.linux.it/listinfo/ltp

-- 
Cyril Hrubis
chrubis@suse.cz