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/*
* test_fsync.c
* test various fsync() methods
*/
#include "postgres.h"
#include "access/xlog_internal.h"
#include "access/xlog.h"
#include "access/xlogdefs.h"
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <stdio.h>
#include <stdlib.h>
#include <time.h>
#include <sys/time.h>
#include <unistd.h>
#include <string.h>
#ifdef WIN32
#define FSYNC_FILENAME "./test_fsync.out"
#else
/* /tmp might be a memory file system */
#define FSYNC_FILENAME "/var/tmp/test_fsync.out"
#endif
#define WRITE_SIZE (16 * 1024)
void die(char *str);
void print_elapse(struct timeval start_t, struct timeval elapse_t);
int
main(int argc, char *argv[])
{
struct timeval start_t;
struct timeval elapse_t;
int tmpfile,
i,
loops = 1000;
char *full_buf = (char *) malloc(XLOG_SEG_SIZE), *buf;
char *filename = FSYNC_FILENAME;
if (argc > 2 && strcmp(argv[1], "-f") == 0)
{
filename = argv[2];
argv += 2;
argc -= 2;
}
if (argc > 1)
loops = atoi(argv[1]);
for (i = 0; i < XLOG_SEG_SIZE; i++)
full_buf[i] = 'a';
if ((tmpfile = open(filename, O_RDWR | O_CREAT, S_IRUSR | S_IWUSR)) == -1)
die("Cannot open output file.");
if (write(tmpfile, full_buf, XLOG_SEG_SIZE) != XLOG_SEG_SIZE)
die("write failed");
/* fsync so later fsync's don't have to do it */
if (fsync(tmpfile) != 0)
die("fsync failed");
close(tmpfile);
buf = (char *)TYPEALIGN(ALIGNOF_XLOG_BUFFER, full_buf);
printf("Simple write timing:\n");
/* write only */
gettimeofday(&start_t, NULL);
for (i = 0; i < loops; i++)
{
if ((tmpfile = open(filename, O_RDWR, 0)) == -1)
die("Cannot open output file.");
if (write(tmpfile, buf, WRITE_SIZE/2) != WRITE_SIZE/2)
die("write failed");
close(tmpfile);
}
gettimeofday(&elapse_t, NULL);
printf("\twrite ");
print_elapse(start_t, elapse_t);
printf("\n");
printf("\nCompare fsync times on write() and non-write() descriptor:\n");
printf("(If the times are similar, fsync() can sync data written\n on a different descriptor.)\n");
/* write, fsync, close */
gettimeofday(&start_t, NULL);
for (i = 0; i < loops; i++)
{
if ((tmpfile = open(filename, O_RDWR, 0)) == -1)
die("Cannot open output file.");
if (write(tmpfile, buf, WRITE_SIZE/2) != WRITE_SIZE/2)
die("write failed");
if (fsync(tmpfile) != 0)
die("fsync failed");
close(tmpfile);
if ((tmpfile = open(filename, O_RDWR, 0)) == -1)
die("Cannot open output file.");
/* do nothing but the open/close the tests are consistent. */
close(tmpfile);
}
gettimeofday(&elapse_t, NULL);
printf("\twrite, fsync, close ");
print_elapse(start_t, elapse_t);
printf("\n");
/* write, close, fsync */
gettimeofday(&start_t, NULL);
for (i = 0; i < loops; i++)
{
if ((tmpfile = open(filename, O_RDWR, 0)) == -1)
die("Cannot open output file.");
if (write(tmpfile, buf, WRITE_SIZE/2) != WRITE_SIZE/2)
die("write failed");
close(tmpfile);
/* reopen file */
if ((tmpfile = open(filename, O_RDWR, 0)) == -1)
die("Cannot open output file.");
if (fsync(tmpfile) != 0)
die("fsync failed");
close(tmpfile);
}
gettimeofday(&elapse_t, NULL);
printf("\twrite, close, fsync ");
print_elapse(start_t, elapse_t);
printf("\n");
printf("\nCompare one o_sync write to two:\n");
#ifdef OPEN_SYNC_FLAG
/* 16k o_sync write */
if ((tmpfile = open(filename, O_RDWR | OPEN_SYNC_FLAG, 0)) == -1)
die("Cannot open output file.");
gettimeofday(&start_t, NULL);
for (i = 0; i < loops; i++)
if (write(tmpfile, buf, WRITE_SIZE) != WRITE_SIZE)
die("write failed");
gettimeofday(&elapse_t, NULL);
close(tmpfile);
printf("\tone 16k o_sync write ");
print_elapse(start_t, elapse_t);
printf("\n");
/* 2*8k o_sync writes */
if ((tmpfile = open(filename, O_RDWR | OPEN_SYNC_FLAG, 0)) == -1)
die("Cannot open output file.");
gettimeofday(&start_t, NULL);
for (i = 0; i < loops; i++)
{
if (write(tmpfile, buf, WRITE_SIZE/2) != WRITE_SIZE/2)
die("write failed");
if (write(tmpfile, buf, WRITE_SIZE/2) != WRITE_SIZE/2)
die("write failed");
}
gettimeofday(&elapse_t, NULL);
close(tmpfile);
printf("\ttwo 8k o_sync writes ");
print_elapse(start_t, elapse_t);
printf("\n");
printf("\nCompare file sync methods with one 8k write:\n");
#else
printf("\t(o_sync unavailable) ");
#endif
printf("\n");
#ifdef OPEN_DATASYNC_FLAG
/* open_dsync, write */
if ((tmpfile = open(filename, O_RDWR | O_DSYNC, 0)) == -1)
die("Cannot open output file.");
gettimeofday(&start_t, NULL);
for (i = 0; i < loops; i++)
if (write(tmpfile, buf, WRITE_SIZE/2) != WRITE_SIZE/2)
die("write failed");
gettimeofday(&elapse_t, NULL);
close(tmpfile);
printf("\topen o_dsync, write ");
print_elapse(start_t, elapse_t);
printf("\n");
#ifdef OPEN_SYNC_FLAG
/* open_fsync, write */
if ((tmpfile = open(filename, O_RDWR | OPEN_SYNC_FLAG, 0)) == -1)
die("Cannot open output file.");
gettimeofday(&start_t, NULL);
for (i = 0; i < loops; i++)
if (write(tmpfile, buf, WRITE_SIZE/2) != WRITE_SIZE/2)
die("write failed");
gettimeofday(&elapse_t, NULL);
close(tmpfile);
printf("\topen o_sync, write ");
print_elapse(start_t, elapse_t);
#endif
#else
printf("\t(o_dsync unavailable) ");
#endif
printf("\n");
#ifdef HAVE_FDATASYNC
/* write, fdatasync */
if ((tmpfile = open(filename, O_RDWR, 0)) == -1)
die("Cannot open output file.");
gettimeofday(&start_t, NULL);
for (i = 0; i < loops; i++)
{
if (write(tmpfile, buf, WRITE_SIZE/2) != WRITE_SIZE/2)
die("write failed");
fdatasync(tmpfile);
}
gettimeofday(&elapse_t, NULL);
close(tmpfile);
printf("\twrite, fdatasync ");
print_elapse(start_t, elapse_t);
#else
printf("\t(fdatasync unavailable)");
#endif
printf("\n");
/* write, fsync, close */
if ((tmpfile = open(filename, O_RDWR, 0)) == -1)
die("Cannot open output file.");
gettimeofday(&start_t, NULL);
for (i = 0; i < loops; i++)
{
if (write(tmpfile, buf, WRITE_SIZE/2) != WRITE_SIZE/2)
die("write failed");
if (fsync(tmpfile) != 0)
die("fsync failed");
}
gettimeofday(&elapse_t, NULL);
close(tmpfile);
printf("\twrite, fsync, ");
print_elapse(start_t, elapse_t);
printf("\n");
printf("\nCompare file sync methods with 2 8k writes:\n");
#ifdef OPEN_DATASYNC_FLAG
/* open_dsync, write */
if ((tmpfile = open(filename, O_RDWR | O_DSYNC, 0)) == -1)
die("Cannot open output file.");
gettimeofday(&start_t, NULL);
for (i = 0; i < loops; i++)
{
if (write(tmpfile, buf, WRITE_SIZE/2) != WRITE_SIZE/2)
die("write failed");
if (write(tmpfile, buf, WRITE_SIZE/2) != WRITE_SIZE/2)
die("write failed");
}
gettimeofday(&elapse_t, NULL);
close(tmpfile);
printf("\topen o_dsync, write ");
print_elapse(start_t, elapse_t);
#else
printf("\t(o_dsync unavailable) ");
#endif
printf("\n");
#ifdef OPEN_SYNC_FLAG
/* open_fsync, write */
if ((tmpfile = open(filename, O_RDWR | OPEN_SYNC_FLAG, 0)) == -1)
die("Cannot open output file.");
gettimeofday(&start_t, NULL);
for (i = 0; i < loops; i++)
{
if (write(tmpfile, buf, WRITE_SIZE/2) != WRITE_SIZE/2)
die("write failed");
if (write(tmpfile, buf, WRITE_SIZE/2) != WRITE_SIZE/2)
die("write failed");
}
gettimeofday(&elapse_t, NULL);
close(tmpfile);
printf("\topen o_sync, write ");
print_elapse(start_t, elapse_t);
printf("\n");
#endif
#ifdef HAVE_FDATASYNC
/* write, fdatasync */
if ((tmpfile = open(filename, O_RDWR, 0)) == -1)
die("Cannot open output file.");
gettimeofday(&start_t, NULL);
for (i = 0; i < loops; i++)
{
if (write(tmpfile, buf, WRITE_SIZE/2) != WRITE_SIZE/2)
die("write failed");
if (write(tmpfile, buf, WRITE_SIZE/2) != WRITE_SIZE/2)
die("write failed");
fdatasync(tmpfile);
}
gettimeofday(&elapse_t, NULL);
close(tmpfile);
printf("\twrite, fdatasync ");
print_elapse(start_t, elapse_t);
#else
printf("\t(fdatasync unavailable)");
#endif
printf("\n");
/* write, fsync, close */
if ((tmpfile = open(filename, O_RDWR, 0)) == -1)
die("Cannot open output file.");
gettimeofday(&start_t, NULL);
for (i = 0; i < loops; i++)
{
if (write(tmpfile, buf, WRITE_SIZE/2) != WRITE_SIZE/2)
die("write failed");
if (write(tmpfile, buf, WRITE_SIZE/2) != WRITE_SIZE/2)
die("write failed");
if (fsync(tmpfile) != 0)
die("fsync failed");
}
gettimeofday(&elapse_t, NULL);
close(tmpfile);
printf("\twrite, fsync, ");
print_elapse(start_t, elapse_t);
printf("\n");
free(full_buf);
unlink(filename);
return 0;
}
void
print_elapse(struct timeval start_t, struct timeval elapse_t)
{
if (elapse_t.tv_usec < start_t.tv_usec)
{
elapse_t.tv_sec--;
elapse_t.tv_usec += 1000000;
}
printf("%3ld.%06ld", (long) (elapse_t.tv_sec - start_t.tv_sec),
(long) (elapse_t.tv_usec - start_t.tv_usec));
}
void
die(char *str)
{
fprintf(stderr, "%s\n", str);
exit(1);
}