On Mon, Feb 13, 2012 at 08:28:03PM -0500, Tom Lane wrote:
> Robert Haas <robertmh...@gmail.com> writes:
> > Instead of or in addition to a fixed number operations per test, maybe
> > we should cut off each test after a certain amount of wall-clock time,
> > like 15 seconds.
>
> +1, I was about to suggest the same thing. Running any of these tests
> for a fixed number of iterations will result in drastic degradation of
> accuracy as soon as the machine's behavior changes noticeably from what
> you were expecting. Run them for a fixed time period instead. Or maybe
> do a few, then check elapsed time and estimate a number of iterations to
> use, if you're worried about the cost of doing gettimeofday after each
> write.
Good idea, and it worked out very well. I changed the -o loops
parameter to -s seconds which calls alarm() after (default) 2 seconds,
and then once the operation completes, computes a duration per
operation.
The test now runs in 30 seconds and produces similar output to the
longer version.
--
Bruce Momjian <br...@momjian.us> http://momjian.us
EnterpriseDB http://enterprisedb.com
+ It's impossible for everything to be true. +
diff --git a/contrib/pg_test_fsync/pg_test_fsync.c b/contrib/pg_test_fsync/pg_test_fsync.c
new file mode 100644
index 3fcb087..8554426
*** a/contrib/pg_test_fsync/pg_test_fsync.c
--- b/contrib/pg_test_fsync/pg_test_fsync.c
***************
*** 27,41 ****
#define NA_FORMAT "%18s"
#define OPS_FORMAT "%9.3f ops/sec"
static const char *progname;
! static int ops_per_test = 2000;
static int needs_unlink = 0;
static char full_buf[XLOG_SEG_SIZE],
*buf,
*filename = FSYNC_FILENAME;
static struct timeval start_t,
stop_t;
static void handle_args(int argc, char *argv[]);
--- 27,50 ----
#define NA_FORMAT "%18s"
#define OPS_FORMAT "%9.3f ops/sec"
+ #define START_TIMER \
+ do { \
+ alarm_triggered = false; \
+ alarm(secs_per_test); \
+ gettimeofday(&start_t, NULL); \
+ } while (0)
+
+
static const char *progname;
! static int secs_per_test = 2;
static int needs_unlink = 0;
static char full_buf[XLOG_SEG_SIZE],
*buf,
*filename = FSYNC_FILENAME;
static struct timeval start_t,
stop_t;
+ static bool alarm_triggered = false;
static void handle_args(int argc, char *argv[]);
*************** static void test_sync(int writes_per_op)
*** 46,57 ****
static void test_open_syncs(void);
static void test_open_sync(const char *msg, int writes_size);
static void test_file_descriptor_sync(void);
static void signal_cleanup(int sig);
#ifdef HAVE_FSYNC_WRITETHROUGH
static int pg_fsync_writethrough(int fd);
#endif
! static void print_elapse(struct timeval start_t, struct timeval stop_t);
static void die(const char *str);
--- 55,67 ----
static void test_open_syncs(void);
static void test_open_sync(const char *msg, int writes_size);
static void test_file_descriptor_sync(void);
+ static void process_alarm(int sig);
static void signal_cleanup(int sig);
#ifdef HAVE_FSYNC_WRITETHROUGH
static int pg_fsync_writethrough(int fd);
#endif
! static void print_elapse(struct timeval start_t, struct timeval stop_t, int ops);
static void die(const char *str);
*************** main(int argc, char *argv[])
*** 65,70 ****
--- 75,81 ----
/* Prevent leaving behind the test file */
signal(SIGINT, signal_cleanup);
signal(SIGTERM, signal_cleanup);
+ signal(SIGALRM, process_alarm);
#ifdef SIGHUP
/* Not defined on win32 */
signal(SIGHUP, signal_cleanup);
*************** handle_args(int argc, char *argv[])
*** 96,102 ****
{
static struct option long_options[] = {
{"filename", required_argument, NULL, 'f'},
! {"ops-per-test", required_argument, NULL, 'o'},
{NULL, 0, NULL, 0}
};
int option; /* Command line option */
--- 107,113 ----
{
static struct option long_options[] = {
{"filename", required_argument, NULL, 'f'},
! {"secs-per-test", required_argument, NULL, 's'},
{NULL, 0, NULL, 0}
};
int option; /* Command line option */
*************** handle_args(int argc, char *argv[])
*** 117,123 ****
}
}
! while ((option = getopt_long(argc, argv, "f:o:",
long_options, &optindex)) != -1)
{
switch (option)
--- 128,134 ----
}
}
! while ((option = getopt_long(argc, argv, "f:s:",
long_options, &optindex)) != -1)
{
switch (option)
*************** handle_args(int argc, char *argv[])
*** 126,133 ****
filename = strdup(optarg);
break;
! case 'o':
! ops_per_test = atoi(optarg);
break;
default:
--- 137,144 ----
filename = strdup(optarg);
break;
! case 's':
! secs_per_test = atoi(optarg);
break;
default:
*************** handle_args(int argc, char *argv[])
*** 148,154 ****
exit(1);
}
! printf("%d operations per test\n", ops_per_test);
#if PG_O_DIRECT != 0
printf("O_DIRECT supported on this platform for open_datasync and open_sync.\n");
#else
--- 159,165 ----
exit(1);
}
! printf("%d seconds per test\n", secs_per_test);
#if PG_O_DIRECT != 0
printf("O_DIRECT supported on this platform for open_datasync and open_sync.\n");
#else
*************** test_sync(int writes_per_op)
*** 220,227 ****
{
if ((tmpfile = open(filename, O_RDWR | O_DSYNC | PG_O_DIRECT, 0)) == -1)
die("could not open output file");
! gettimeofday(&start_t, NULL);
! for (ops = 0; ops < ops_per_test; ops++)
{
for (writes = 0; writes < writes_per_op; writes++)
if (write(tmpfile, buf, XLOG_BLCKSZ) != XLOG_BLCKSZ)
--- 231,238 ----
{
if ((tmpfile = open(filename, O_RDWR | O_DSYNC | PG_O_DIRECT, 0)) == -1)
die("could not open output file");
! START_TIMER;
! for (ops = 0; alarm_triggered == false; ops++)
{
for (writes = 0; writes < writes_per_op; writes++)
if (write(tmpfile, buf, XLOG_BLCKSZ) != XLOG_BLCKSZ)
*************** test_sync(int writes_per_op)
*** 231,237 ****
}
gettimeofday(&stop_t, NULL);
close(tmpfile);
! print_elapse(start_t, stop_t);
}
#else
printf(NA_FORMAT, "n/a\n");
--- 242,248 ----
}
gettimeofday(&stop_t, NULL);
close(tmpfile);
! print_elapse(start_t, stop_t, ops);
}
#else
printf(NA_FORMAT, "n/a\n");
*************** test_sync(int writes_per_op)
*** 246,253 ****
#ifdef HAVE_FDATASYNC
if ((tmpfile = open(filename, O_RDWR, 0)) == -1)
die("could not open output file");
! gettimeofday(&start_t, NULL);
! for (ops = 0; ops < ops_per_test; ops++)
{
for (writes = 0; writes < writes_per_op; writes++)
if (write(tmpfile, buf, XLOG_BLCKSZ) != XLOG_BLCKSZ)
--- 257,264 ----
#ifdef HAVE_FDATASYNC
if ((tmpfile = open(filename, O_RDWR, 0)) == -1)
die("could not open output file");
! START_TIMER;
! for (ops = 0; alarm_triggered == false; ops++)
{
for (writes = 0; writes < writes_per_op; writes++)
if (write(tmpfile, buf, XLOG_BLCKSZ) != XLOG_BLCKSZ)
*************** test_sync(int writes_per_op)
*** 258,264 ****
}
gettimeofday(&stop_t, NULL);
close(tmpfile);
! print_elapse(start_t, stop_t);
#else
printf(NA_FORMAT, "n/a\n");
#endif
--- 269,275 ----
}
gettimeofday(&stop_t, NULL);
close(tmpfile);
! print_elapse(start_t, stop_t, ops);
#else
printf(NA_FORMAT, "n/a\n");
#endif
*************** test_sync(int writes_per_op)
*** 271,278 ****
if ((tmpfile = open(filename, O_RDWR, 0)) == -1)
die("could not open output file");
! gettimeofday(&start_t, NULL);
! for (ops = 0; ops < ops_per_test; ops++)
{
for (writes = 0; writes < writes_per_op; writes++)
if (write(tmpfile, buf, XLOG_BLCKSZ) != XLOG_BLCKSZ)
--- 282,289 ----
if ((tmpfile = open(filename, O_RDWR, 0)) == -1)
die("could not open output file");
! START_TIMER;
! for (ops = 0; alarm_triggered == false; ops++)
{
for (writes = 0; writes < writes_per_op; writes++)
if (write(tmpfile, buf, XLOG_BLCKSZ) != XLOG_BLCKSZ)
*************** test_sync(int writes_per_op)
*** 284,290 ****
}
gettimeofday(&stop_t, NULL);
close(tmpfile);
! print_elapse(start_t, stop_t);
/*
* If fsync_writethrough is available, test as well
--- 295,301 ----
}
gettimeofday(&stop_t, NULL);
close(tmpfile);
! print_elapse(start_t, stop_t, ops);
/*
* If fsync_writethrough is available, test as well
*************** test_sync(int writes_per_op)
*** 295,302 ****
#ifdef HAVE_FSYNC_WRITETHROUGH
if ((tmpfile = open(filename, O_RDWR, 0)) == -1)
die("could not open output file");
! gettimeofday(&start_t, NULL);
! for (ops = 0; ops < ops_per_test; ops++)
{
for (writes = 0; writes < writes_per_op; writes++)
if (write(tmpfile, buf, XLOG_BLCKSZ) != XLOG_BLCKSZ)
--- 306,313 ----
#ifdef HAVE_FSYNC_WRITETHROUGH
if ((tmpfile = open(filename, O_RDWR, 0)) == -1)
die("could not open output file");
! START_TIMER;
! for (ops = 0; alarm_triggered == false; ops++)
{
for (writes = 0; writes < writes_per_op; writes++)
if (write(tmpfile, buf, XLOG_BLCKSZ) != XLOG_BLCKSZ)
*************** test_sync(int writes_per_op)
*** 308,314 ****
}
gettimeofday(&stop_t, NULL);
close(tmpfile);
! print_elapse(start_t, stop_t);
#else
printf(NA_FORMAT, "n/a\n");
#endif
--- 319,325 ----
}
gettimeofday(&stop_t, NULL);
close(tmpfile);
! print_elapse(start_t, stop_t, ops);
#else
printf(NA_FORMAT, "n/a\n");
#endif
*************** test_sync(int writes_per_op)
*** 327,334 ****
}
else
{
! gettimeofday(&start_t, NULL);
! for (ops = 0; ops < ops_per_test; ops++)
{
for (writes = 0; writes < writes_per_op; writes++)
if (write(tmpfile, buf, XLOG_BLCKSZ) != XLOG_BLCKSZ)
--- 338,345 ----
}
else
{
! START_TIMER;
! for (ops = 0; alarm_triggered == false; ops++)
{
for (writes = 0; writes < writes_per_op; writes++)
if (write(tmpfile, buf, XLOG_BLCKSZ) != XLOG_BLCKSZ)
*************** test_sync(int writes_per_op)
*** 338,344 ****
}
gettimeofday(&stop_t, NULL);
close(tmpfile);
! print_elapse(start_t, stop_t);
}
#else
printf(NA_FORMAT, "n/a\n");
--- 349,355 ----
}
gettimeofday(&stop_t, NULL);
close(tmpfile);
! print_elapse(start_t, stop_t, ops);
}
#else
printf(NA_FORMAT, "n/a\n");
*************** test_open_sync(const char *msg, int writ
*** 385,392 ****
printf(NA_FORMAT, "n/a*\n");
else
{
! gettimeofday(&start_t, NULL);
! for (ops = 0; ops < ops_per_test; ops++)
{
for (writes = 0; writes < 16 / writes_size; writes++)
if (write(tmpfile, buf, writes_size * 1024) !=
--- 396,403 ----
printf(NA_FORMAT, "n/a*\n");
else
{
! START_TIMER;
! for (ops = 0; alarm_triggered == false; ops++)
{
for (writes = 0; writes < 16 / writes_size; writes++)
if (write(tmpfile, buf, writes_size * 1024) !=
*************** test_open_sync(const char *msg, int writ
*** 397,403 ****
}
gettimeofday(&stop_t, NULL);
close(tmpfile);
! print_elapse(start_t, stop_t);
}
#else
printf(NA_FORMAT, "n/a\n");
--- 408,414 ----
}
gettimeofday(&stop_t, NULL);
close(tmpfile);
! print_elapse(start_t, stop_t, ops);
}
#else
printf(NA_FORMAT, "n/a\n");
*************** test_file_descriptor_sync(void)
*** 427,434 ****
printf(LABEL_FORMAT, "write, fsync, close");
fflush(stdout);
! gettimeofday(&start_t, NULL);
! for (ops = 0; ops < ops_per_test; ops++)
{
if ((tmpfile = open(filename, O_RDWR, 0)) == -1)
die("could not open output file");
--- 438,445 ----
printf(LABEL_FORMAT, "write, fsync, close");
fflush(stdout);
! START_TIMER;
! for (ops = 0; alarm_triggered == false; ops++)
{
if ((tmpfile = open(filename, O_RDWR, 0)) == -1)
die("could not open output file");
*************** test_file_descriptor_sync(void)
*** 447,453 ****
close(tmpfile);
}
gettimeofday(&stop_t, NULL);
! print_elapse(start_t, stop_t);
/*
* Now open, write, close, open again and fsync This simulates processes
--- 458,464 ----
close(tmpfile);
}
gettimeofday(&stop_t, NULL);
! print_elapse(start_t, stop_t, ops);
/*
* Now open, write, close, open again and fsync This simulates processes
*************** test_file_descriptor_sync(void)
*** 456,463 ****
printf(LABEL_FORMAT, "write, close, fsync");
fflush(stdout);
! gettimeofday(&start_t, NULL);
! for (ops = 0; ops < ops_per_test; ops++)
{
if ((tmpfile = open(filename, O_RDWR, 0)) == -1)
die("could not open output file");
--- 467,474 ----
printf(LABEL_FORMAT, "write, close, fsync");
fflush(stdout);
! START_TIMER;
! for (ops = 0; alarm_triggered == false; ops++)
{
if ((tmpfile = open(filename, O_RDWR, 0)) == -1)
die("could not open output file");
*************** test_file_descriptor_sync(void)
*** 472,478 ****
close(tmpfile);
}
gettimeofday(&stop_t, NULL);
! print_elapse(start_t, stop_t);
}
--- 483,489 ----
close(tmpfile);
}
gettimeofday(&stop_t, NULL);
! print_elapse(start_t, stop_t, ops);
}
*************** test_non_sync(void)
*** 489,496 ****
printf(LABEL_FORMAT, "write");
fflush(stdout);
! gettimeofday(&start_t, NULL);
! for (ops = 0; ops < ops_per_test; ops++)
{
if ((tmpfile = open(filename, O_RDWR, 0)) == -1)
die("could not open output file");
--- 500,507 ----
printf(LABEL_FORMAT, "write");
fflush(stdout);
! START_TIMER;
! for (ops = 0; alarm_triggered == false; ops++)
{
if ((tmpfile = open(filename, O_RDWR, 0)) == -1)
die("could not open output file");
*************** test_non_sync(void)
*** 499,505 ****
close(tmpfile);
}
gettimeofday(&stop_t, NULL);
! print_elapse(start_t, stop_t);
}
static void
--- 510,516 ----
close(tmpfile);
}
gettimeofday(&stop_t, NULL);
! print_elapse(start_t, stop_t, ops);
}
static void
*************** pg_fsync_writethrough(int fd)
*** 533,548 ****
* print out the writes per second for tests
*/
static void
! print_elapse(struct timeval start_t, struct timeval stop_t)
{
double total_time = (stop_t.tv_sec - start_t.tv_sec) +
(stop_t.tv_usec - start_t.tv_usec) * 0.000001;
! double per_second = ops_per_test / total_time;
printf(OPS_FORMAT "\n", per_second);
}
static void
die(const char *str)
{
fprintf(stderr, "%s: %s\n", str, strerror(errno));
--- 544,565 ----
* print out the writes per second for tests
*/
static void
! print_elapse(struct timeval start_t, struct timeval stop_t, int ops)
{
double total_time = (stop_t.tv_sec - start_t.tv_sec) +
(stop_t.tv_usec - start_t.tv_usec) * 0.000001;
! double per_second = ops / total_time;
printf(OPS_FORMAT "\n", per_second);
}
static void
+ process_alarm(int sig)
+ {
+ alarm_triggered = true;
+ }
+
+ static void
die(const char *str)
{
fprintf(stderr, "%s: %s\n", str, strerror(errno));
diff --git a/doc/src/sgml/pgtestfsync.sgml b/doc/src/sgml/pgtestfsync.sgml
new file mode 100644
index 2889059..ba9f0c1
*** a/doc/src/sgml/pgtestfsync.sgml
--- b/doc/src/sgml/pgtestfsync.sgml
*************** pg_test_fsync [options]
*** 47,59 ****
</varlistentry>
<varlistentry>
! <term><option>-o</option></term>
! <term><option>--ops-per-test</option></term>
<listitem>
<para>
! Specifies the number of operations per test. The more operations
per test, the greater the test's accuracy, but the longer it takes
! to run. The default is 2000.
</para>
</listitem>
</varlistentry>
--- 47,59 ----
</varlistentry>
<varlistentry>
! <term><option>-s</option></term>
! <term><option>--secs-per-test</option></term>
<listitem>
<para>
! Specifies the number of seconds for each test. The more time
per test, the greater the test's accuracy, but the longer it takes
! to run. The default is 2 seconds.
</para>
</listitem>
</varlistentry>
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