> + 	if ((lasttime->tv_sec == 0 && lasttime->tv_usec == 0) ||
> + 	    delta.tv_sec > 0) {
> + 		*lasttime = mono_time;
> + 		*curpps = 0;
> + 		rv = 1;
> + 	} else if (*curpps < maxpps)
> + 		rv = 1;
> + 	else
> + 		rv = 0;
> + 	/* be careful about wrap-around */
> + 	if (*curpps + 1 > *curpps)
> + 		*curpps = *curpps + 1;

If it reached to the limit, we don't need to increment it, do we?  And
if we aren't reached to the limit yet, we can safely increment it.  I.e.,

if (needtoreset) {
	*cur = 1;
	return (1);
} else if (*cur < max) {
	(*cur)++;
	return (1);
} else
	return (0);

> 	you may have different idea about function names or argument types,
> 	i'm not good at naming things:-)

psratecheck (per second rate check)?  I'll strongly agree with you
that at least the acronym pps isn't generic enough.

enami.