writetest.cs

/*
 * writetest --
 *
 * $Id: writetest.cs,v 10.8 2005/09/13 18:15:36 bostic Exp $
 */
#include <sys/types.h>
#include <sys/time.h>

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

void usage(void);

int
main(argc, argv)
        int argc;
        char *argv[];
{
        struct timeval start_time, end_time;
        double usecs;
        long val;
        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);

        /*
         * Guarantee end_time fields are greater than or equal to start_time
         * fields.
         */
        if (end_time.tv_sec > start_time.tv_sec) {
                --end_time.tv_sec;
                end_time.tv_usec += 1000000;
        }

        /* Display elapsed time. */
        val = end_time.tv_sec - start_time.tv_sec;
        printf("Elapsed time: %ld:", val / (60 * 60));
        val %= 60 * 60;
        printf("%ld:", val / 60);
        val %= 60;
        printf("%ld.%ld\n", val, end_time.tv_usec - start_time.tv_usec);

        /* Display operations per second. */
        usecs =
            (end_time.tv_sec - start_time.tv_sec) * 1000000 +
            (end_time.tv_usec - start_time.tv_usec);
        printf("%d operations: %7.2f operations per second\n",
            ops, (ops / usecs) * 1000000);

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

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

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