writetest.txt

介绍：MySQL是比较出名的数据库软件

/*
 * writetest --
 *
 * $Id: writetest.txt,v 10.3 1999/11/19 17:21:06 bostic Exp $
 */
#include <sys/types.h>

#include <errno.h>
#include <fcntl.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <time.h>
#include <unistd.h>

void usage __P((void));

int
main(argc, argv)
	int argc;
	char *argv[];
{
	struct timeval start_time, end_time;
	long usecs;
	int bytes, ch, cnt, fd, ops;
	char *fname, buf[100 * 1024];

	bytes = 256;
	fname = "testfile";
	ops = 1000;
	while ((ch = getopt(argc, argv, "b:f:o:")) != EOF)
		switch (ch) {
		case 'b':
			if ((bytes = atoi(optarg)) > sizeof(buf)) {
				fprintf(stderr,
				    "max -b option %d\n", sizeof(buf));
				exit (1);
			}
			break;
		case 'f':
			fname = optarg;
			break;
		case 'o':
			if ((ops = atoi(optarg)) <= 0) {
				fprintf(stderr, "illegal -o option value\n");
				exit (1);
			}
			break;
		case '?':
		default:
			usage();
		}
	argc -= optind;
	argv += optind;

	(void)unlink(fname);
	if ((fd = open(fname, O_RDWR | O_CREAT, 0666)) == -1) {
		perror(fname);
		exit (1);
	}

	memset(buf, 0, bytes);

	printf("running: %d ops\n", ops);

	(void)gettimeofday(&start_time, NULL);
	for (cnt = 0; cnt < ops; ++cnt) {
		if (write(fd, buf, bytes) != bytes) {
			fprintf(stderr, "write: %s\n", strerror(errno));
			exit (1);
		}
		if (lseek(fd, (off_t)0, SEEK_SET) == -1) {
			fprintf(stderr, "lseek: %s\n", strerror(errno));
			exit (1);
		}
		if (fsync(fd) != 0) {
			fprintf(stderr, "fsync: %s\n", strerror(errno));
			exit (1);
		}
	}
	(void)gettimeofday(&end_time, NULL);

	usecs = (end_time.tv_sec - start_time.tv_sec) * 1000000 +
	    end_time.tv_usec - start_time.tv_usec;
	printf("Elapsed time: %ld.%06ld seconds\n",
	    usecs / 1000000, usecs % 1000000);
	printf("%d ops: %7.2f ops per second\n",
	    ops, (float)1000000 * ops/usecs);

	(void)unlink(fname);
	exit (0);
}

void
usage()
{
	(void)fprintf(stderr,
	    "usage: testfile [-b bytes] [-f file] [-o ops]\n");
	exit(1);
}