[LTP] [RFC] [PATCH] pselect01: Tune thresholds

Cyril Hrubis
2017-05-12T06:51:31Z

Hi!
> > +static int compute_threshold(long long requested_us, unsigned int
> > iterations)
> > +{
> > + unsigned int slack_per_run = MIN(100000, requested_us / 1000);
> > +
> > + return (40 + slack_per_run) * iterations + 20000 / (iterations/200 + 1);
> > +}
>
> requested_us = tst_timespec_to_us(t->tv) * t->iterations;
>
> If slack_per_run is slack of all iterations, why is it multiplied
> again with number of iterations?

That variable is poorly named. It should have been slack_per_call or
slack_per_iteration. It's slack per one syscall computed using the same
formula that is used in kernel...