/*
 * bw_mmap_rd.c - time reading & summing of a file using mmap
 *
 * Usage: bw_mmap_rd size file
 *
 * Sizes less than 2m are not recommended.  Memory is read by summing it up
 * so the numbers include the cost of the adds.  If you use sizes large
 * enough, you can compare to bw_mem_rd and get the cost of TLB fills 
 * (very roughly).
 *
 * Copyright (c) 1994 Larry McVoy.  Distributed under the FSF GPL with
 * additional restriction that results may published only if
 * (1) the benchmark is unmodified, and
 * (2) the version in the sccsid below is included in the report.
 * Support for this development by Sun Microsystems is gratefully acknowledged.
 */
char	*id = "$Id$\n";

#include "bench.h"
#ifdef MAP_FILE
#	define	MMAP_FLAGS	MAP_FILE|MAP_SHARED
#else
#	define	MMAP_FLAGS	MAP_SHARED
#endif

#define	TYPE	int
#define	MINSZ	(sizeof(TYPE) * 128)
#define	CHK(x)	if ((long)(x) == -1) { perror("x"); exit(1); }

void
doit(register TYPE *p, register TYPE *lastone)
{
	register int sum = 0;

	while (p <= lastone) {
	    sum += p[0]+p[1]+p[2]+p[3]+p[4]+p[5]+p[6]+p[7]+p[8]+
	    p[9]+p[10]+p[11]+p[12]+p[13]+p[14]+p[15]+p[16]+p[17]+
	    p[18]+p[19]+p[20]+p[21]+p[22]+p[23]+p[24]+p[25]+p[26]+
	    p[27]+p[28]+p[29]+p[30]+p[31]+p[32]+p[33]+p[34]+p[35]+
	    p[36]+p[37]+p[38]+p[39]+p[40]+p[41]+p[42]+p[43]+
	    p[44]+p[45]+p[46]+p[47]+p[48]+p[49]+p[50]+p[51]+
	    p[52]+p[53]+p[54]+p[55]+p[56]+p[57]+p[58]+p[59]+
	    p[60]+p[61]+p[62]+p[63]+p[64]+p[65]+p[66]+p[67]+
	    p[68]+p[69]+p[70]+p[71]+p[72]+p[73]+p[74]+p[75]+
	    p[76]+p[77]+p[78]+p[79]+p[80]+p[81]+p[82]+p[83]+
	    p[84]+p[85]+p[86]+p[87]+p[88]+p[89]+p[90]+p[91]+
	    p[92]+p[93]+p[94]+p[95]+p[96]+p[97]+p[98]+p[99]+
	    p[100]+p[101]+p[102]+p[103]+p[104]+p[105]+p[106]+
	    p[107]+p[108]+p[109]+p[110]+p[111]+p[112]+p[113]+
	    p[114]+p[115]+p[116]+p[117]+p[118]+p[119]+p[120]+
	    p[121]+p[122]+p[123]+p[124]+p[125]+p[126]+p[127];
	    p += 128;
	}
	use_int(sum);
}

void
time_with_open(char *file, int nbytes)
{
	int	fd;
	TYPE	*buf, *lastone;

	CHK(fd = open(file, 0));
	CHK(buf = (TYPE*)mmap(0, nbytes, PROT_READ, MMAP_FLAGS, fd, 0));
	lastone = (TYPE*)((char*)buf + nbytes - MINSZ);
	doit(buf, lastone);
	close(fd);
	munmap((void*)buf, nbytes);
}

int
main(int ac, char **av)
{
	int	fd, nbytes;
	struct	stat sbuf;
	TYPE	*buf, *lastone;

	if (ac != 4) {
		fprintf(stderr,
		    "Usage: %s size open2close|mmap_only file\n", av[0]);
		exit(1);
	}
	nbytes = bytes(av[1]);
	CHK(stat(av[3], &sbuf));
	if ((nbytes > sbuf.st_size) || (nbytes < MINSZ)) {
		exit(1);
	}

	if (!strcmp("open2close", av[2])) {
		BENCH(time_with_open(av[3], nbytes), 0);
	} else {
		CHK(fd = open(av[3], 0));
		CHK(buf = (TYPE*)mmap(0, nbytes, PROT_READ, MMAP_FLAGS, fd, 0));
		lastone = (TYPE*)((char*)buf + nbytes - MINSZ);
		BENCH(doit(buf, lastone), 0);
		munmap((void*)buf, nbytes);
	}
	bandwidth(nbytes, get_n(), 0);
	return (0);
}