
null syscall:		528
single byte pread:	1026
single byte preadv:	1134
fincore (miss):		674
fincore (hit):		729

	if (fincore(fd, NULL, offset, len) == len)
		pread();
	else
		punt();

	if (preadv2(fd, ..., offset, len) == len)
		...
	else
		punt();

fincore, hit:	1755
fincore, miss:	674
preadv2:	1026

average = hitrate * hitcost + (1 - hitrate) * misscost

average = hitrate * hitcost + misscost - hitrate * misscost

average - misscost = hitrate * hitcost - hitrate * misscost

average - misscost = hitrate * (hitcost - misscost)

(average - misscost) / (hitcost - misscost) = hitrate

(1026 - 674) / (1755 - 674) = 0.3256



