/* Copyright 2005 Intel Corporation.  All Rights Reserved.
 * Please distribute under the terms of the GPLv2 or later.
 * Written by Benjamin LaHaise.
 */
#define _GNU_SOURCE	1
#include <stdio.h>
#include <stdlib.h>
#include <errno.h>
#include <sys/mman.h>
#include <libaio.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>

#define NR_BUFFERS	20480
#define BUFSIZE		512
#define BLOCKSIZE	4096

int main(int argc, char *argv[])
{
	long bufsize = BUFSIZE;
	struct iocb ios[NR_BUFFERS], *iocbps[NR_BUFFERS];
	struct io_event events[NR_BUFFERS];
	io_context_t ctx;
	char *buffers;
	long err;
	int i, completed;
	int min_nr = NR_BUFFERS;
	int repeats = 1;
	int j;
	int fd;
	long total = 0;

	if (argc > 1 && !strcmp("--bufsize", argv[1])) {
		bufsize = atol(argv[2]);
		argv += 2;
		argc -= 2;
		if (bufsize & 511) {
			fprintf(stderr, "bufsize must be a multiple of 512\n");
			exit(2);
		}
		printf("bufsize %ld\n", bufsize);
	}
	if (argc > 1)
		min_nr = atoi(argv[1]);
	if (min_nr < 1)
		min_nr = 1;
	if (argc > 2)
		repeats = atoi(argv[2]);
	if (repeats < 1)
		repeats = 1;

	fd = open("testfile", O_RDONLY | O_DIRECT);
	if (fd < 0) {
		perror("open(testfile, O_RDONLY|O_DIRECT)");
		exit(1);
	}

	buffers = mmap(NULL, NR_BUFFERS * bufsize, PROT_READ|PROT_WRITE,
			MAP_PRIVATE | MAP_ANONYMOUS, -1, 0);
	if (MAP_FAILED == (void *)buffers) {
		perror("mmap");
		exit(1);
	}

	memset(buffers, 0, NR_BUFFERS * bufsize);

	err = io_setup(NR_BUFFERS * 2, &ctx);
	if (err) {
		fprintf(stderr, "io_setup: %ld: %s\n", err, strerror(-err));
		exit(1);
	}

	for (i=0; i<NR_BUFFERS; i++) {
		io_prep_pread(&ios[i], fd, buffers+(i * bufsize), bufsize, 
				i * BLOCKSIZE);
		iocbps[i] = &ios[i];
	}

	printf("waiting for min_nr = %d events per loop, %d loops bufsize = %ld\n", min_nr,
		repeats, bufsize);

	for (j=0; j<repeats; j++) {
	err = io_submit(ctx, NR_BUFFERS, iocbps);
	if (err != NR_BUFFERS) {
		fprintf(stderr, "io_submit: %ld vs %d: %s\n", err, NR_BUFFERS, 
			strerror(-err));
		exit(1);
	}


	for (completed=0; completed<NR_BUFFERS; completed+=err) {
		int left = NR_BUFFERS - completed;
		err = io_getevents(ctx, (left < min_nr) ? left : min_nr,
				   NR_BUFFERS, events, NULL);
		if (err <= 0) {
			fprintf(stderr, "io_getevents: %ld vs %d: %s\n", err,
				NR_BUFFERS-completed, strerror(-err));
			exit(1);
		}

		for (i=0; i<err; i++) {
			if (events[i].res > 0)
				total += events[i].res;
			if (bufsize == events[i].res)
				continue;
			if ((long)events[i].res < 0) {
				int idx = events[i].obj - ios;
				fprintf(stderr, "iocb[%d] = %ld\n", idx,
					events[i].res);
			}
		}
	}
	}
	printf("completed %d repeats.  read a total of %ld bytes\n", j, total);
	return 0;
}