PostgreSQL Source Code  git master
pg_test_fsync.c
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1 /*
2  * pg_test_fsync.c
3  * tests all supported fsync() methods
4  */
5 
6 #include "postgres_fe.h"
7 
8 #include <limits.h>
9 #include <sys/stat.h>
10 #include <sys/time.h>
11 #include <fcntl.h>
12 #include <time.h>
13 #include <unistd.h>
14 #include <signal.h>
15 
16 #include "access/xlogdefs.h"
17 #include "common/logging.h"
18 #include "common/pg_prng.h"
19 #include "getopt_long.h"
20 
21 /*
22  * put the temp files in the local directory
23  * unless the user specifies otherwise
24  */
25 #define FSYNC_FILENAME "./pg_test_fsync.out"
26 
27 #define XLOG_BLCKSZ_K (XLOG_BLCKSZ / 1024)
28 
29 #define LABEL_FORMAT " %-30s"
30 #define NA_FORMAT "%21s\n"
31 /* translator: maintain alignment with NA_FORMAT */
32 #define OPS_FORMAT gettext_noop("%13.3f ops/sec %6.0f usecs/op\n")
33 #define USECS_SEC 1000000
34 
35 /* These are macros to avoid timing the function call overhead. */
36 #ifndef WIN32
37 #define START_TIMER \
38 do { \
39  alarm_triggered = false; \
40  alarm(secs_per_test); \
41  gettimeofday(&start_t, NULL); \
42 } while (0)
43 #else
44 /* WIN32 doesn't support alarm, so we create a thread and sleep there */
45 #define START_TIMER \
46 do { \
47  alarm_triggered = false; \
48  if (CreateThread(NULL, 0, process_alarm, NULL, 0, NULL) == \
49  INVALID_HANDLE_VALUE) \
50  pg_fatal("could not create thread for alarm"); \
51  gettimeofday(&start_t, NULL); \
52 } while (0)
53 #endif
54 
55 #define STOP_TIMER \
56 do { \
57  gettimeofday(&stop_t, NULL); \
58  print_elapse(start_t, stop_t, ops); \
59 } while (0)
60 
61 
62 static const char *progname;
63 
64 static unsigned int secs_per_test = 5;
65 static int needs_unlink = 0;
67  *buf,
69 static struct timeval start_t,
70  stop_t;
71 static bool alarm_triggered = false;
72 
73 
74 static void handle_args(int argc, char *argv[]);
75 static void prepare_buf(void);
76 static void test_open(void);
77 static void test_non_sync(void);
78 static void test_sync(int writes_per_op);
79 static void test_open_syncs(void);
80 static void test_open_sync(const char *msg, int writes_size);
81 static void test_file_descriptor_sync(void);
82 
83 #ifndef WIN32
84 static void process_alarm(SIGNAL_ARGS);
85 #else
86 static DWORD WINAPI process_alarm(LPVOID param);
87 #endif
88 static void signal_cleanup(SIGNAL_ARGS);
89 
90 #ifdef HAVE_FSYNC_WRITETHROUGH
91 static int pg_fsync_writethrough(int fd);
92 #endif
93 static void print_elapse(struct timeval start_t, struct timeval stop_t, int ops);
94 
95 #define die(msg) pg_fatal("%s: %m", _(msg))
96 
97 
98 int
99 main(int argc, char *argv[])
100 {
101  pg_logging_init(argv[0]);
102  set_pglocale_pgservice(argv[0], PG_TEXTDOMAIN("pg_test_fsync"));
103  progname = get_progname(argv[0]);
104 
105  handle_args(argc, argv);
106 
107  /* Prevent leaving behind the test file */
108  pqsignal(SIGINT, signal_cleanup);
109  pqsignal(SIGTERM, signal_cleanup);
110 #ifndef WIN32
112 #endif
113 #ifdef SIGHUP
114  /* Not defined on win32 */
116 #endif
117 
118  pg_prng_seed(&pg_global_prng_state, (uint64) time(NULL));
119 
120  prepare_buf();
121 
122  test_open();
123 
124  /* Test using 1 XLOG_BLCKSZ write */
125  test_sync(1);
126 
127  /* Test using 2 XLOG_BLCKSZ writes */
128  test_sync(2);
129 
130  test_open_syncs();
131 
133 
134  test_non_sync();
135 
136  unlink(filename);
137 
138  return 0;
139 }
140 
141 static void
142 handle_args(int argc, char *argv[])
143 {
144  static struct option long_options[] = {
145  {"filename", required_argument, NULL, 'f'},
146  {"secs-per-test", required_argument, NULL, 's'},
147  {NULL, 0, NULL, 0}
148  };
149 
150  int option; /* Command line option */
151  int optindex = 0; /* used by getopt_long */
152  unsigned long optval; /* used for option parsing */
153  char *endptr;
154 
155  if (argc > 1)
156  {
157  if (strcmp(argv[1], "--help") == 0 || strcmp(argv[1], "-?") == 0)
158  {
159  printf(_("Usage: %s [-f FILENAME] [-s SECS-PER-TEST]\n"), progname);
160  exit(0);
161  }
162  if (strcmp(argv[1], "--version") == 0 || strcmp(argv[1], "-V") == 0)
163  {
164  puts("pg_test_fsync (PostgreSQL) " PG_VERSION);
165  exit(0);
166  }
167  }
168 
169  while ((option = getopt_long(argc, argv, "f:s:",
170  long_options, &optindex)) != -1)
171  {
172  switch (option)
173  {
174  case 'f':
176  break;
177 
178  case 's':
179  errno = 0;
180  optval = strtoul(optarg, &endptr, 10);
181 
182  if (endptr == optarg || *endptr != '\0' ||
183  errno != 0 || optval != (unsigned int) optval)
184  {
185  pg_log_error("invalid argument for option %s", "--secs-per-test");
186  pg_log_error_hint("Try \"%s --help\" for more information.", progname);
187  exit(1);
188  }
189 
190  secs_per_test = (unsigned int) optval;
191  if (secs_per_test == 0)
192  pg_fatal("%s must be in range %u..%u",
193  "--secs-per-test", 1, UINT_MAX);
194  break;
195 
196  default:
197  /* getopt_long already emitted a complaint */
198  pg_log_error_hint("Try \"%s --help\" for more information.", progname);
199  exit(1);
200  }
201  }
202 
203  if (argc > optind)
204  {
205  pg_log_error("too many command-line arguments (first is \"%s\")",
206  argv[optind]);
207  pg_log_error_hint("Try \"%s --help\" for more information.", progname);
208  exit(1);
209  }
210 
211  printf(ngettext("%u second per test\n",
212  "%u seconds per test\n",
213  secs_per_test),
214  secs_per_test);
215 #if defined(O_DIRECT)
216  printf(_("O_DIRECT supported on this platform for open_datasync and open_sync.\n"));
217 #elif defined(F_NOCACHE)
218  printf(_("F_NOCACHE supported on this platform for open_datasync and open_sync.\n"));
219 #else
220  printf(_("Direct I/O is not supported on this platform.\n"));
221 #endif
222 }
223 
224 static void
226 {
227  int ops;
228 
229  /* write random data into buffer */
230  for (ops = 0; ops < DEFAULT_XLOG_SEG_SIZE; ops++)
232 
233  buf = (char *) TYPEALIGN(XLOG_BLCKSZ, full_buf);
234 }
235 
236 static void
238 {
239  int tmpfile;
240 
241  /*
242  * test if we can open the target file
243  */
244  if ((tmpfile = open(filename, O_RDWR | O_CREAT | PG_BINARY, S_IRUSR | S_IWUSR)) == -1)
245  die("could not open output file");
246  needs_unlink = 1;
247  if (write(tmpfile, full_buf, DEFAULT_XLOG_SEG_SIZE) !=
249  die("write failed");
250 
251  /* fsync now so that dirty buffers don't skew later tests */
252  if (fsync(tmpfile) != 0)
253  die("fsync failed");
254 
255  close(tmpfile);
256 }
257 
258 static int
259 open_direct(const char *path, int flags, mode_t mode)
260 {
261  int fd;
262 
263 #ifdef O_DIRECT
264  flags |= O_DIRECT;
265 #endif
266 
267  fd = open(path, flags, mode);
268 
269 #if !defined(O_DIRECT) && defined(F_NOCACHE)
270  if (fd >= 0 && fcntl(fd, F_NOCACHE, 1) < 0)
271  {
272  int save_errno = errno;
273 
274  close(fd);
275  errno = save_errno;
276  return -1;
277  }
278 #endif
279 
280  return fd;
281 }
282 
283 static void
284 test_sync(int writes_per_op)
285 {
286  int tmpfile,
287  ops,
288  writes;
289  bool fs_warning = false;
290 
291  if (writes_per_op == 1)
292  printf(_("\nCompare file sync methods using one %dkB write:\n"), XLOG_BLCKSZ_K);
293  else
294  printf(_("\nCompare file sync methods using two %dkB writes:\n"), XLOG_BLCKSZ_K);
295  printf(_("(in wal_sync_method preference order, except fdatasync is Linux's default)\n"));
296 
297  /*
298  * Test open_datasync if available
299  */
300  printf(LABEL_FORMAT, "open_datasync");
301  fflush(stdout);
302 
303 #ifdef O_DSYNC
304  if ((tmpfile = open_direct(filename, O_RDWR | O_DSYNC | PG_BINARY, 0)) == -1)
305  {
306  printf(NA_FORMAT, _("n/a*"));
307  fs_warning = true;
308  }
309  else
310  {
311  START_TIMER;
312  for (ops = 0; alarm_triggered == false; ops++)
313  {
314  for (writes = 0; writes < writes_per_op; writes++)
315  if (pg_pwrite(tmpfile,
316  buf,
317  XLOG_BLCKSZ,
318  writes * XLOG_BLCKSZ) != XLOG_BLCKSZ)
319  die("write failed");
320  }
321  STOP_TIMER;
322  close(tmpfile);
323  }
324 #else
325  printf(NA_FORMAT, _("n/a"));
326 #endif
327 
328 /*
329  * Test fdatasync if available
330  */
331  printf(LABEL_FORMAT, "fdatasync");
332  fflush(stdout);
333 
334  if ((tmpfile = open(filename, O_RDWR | PG_BINARY, 0)) == -1)
335  die("could not open output file");
336  START_TIMER;
337  for (ops = 0; alarm_triggered == false; ops++)
338  {
339  for (writes = 0; writes < writes_per_op; writes++)
340  if (pg_pwrite(tmpfile,
341  buf,
342  XLOG_BLCKSZ,
343  writes * XLOG_BLCKSZ) != XLOG_BLCKSZ)
344  die("write failed");
345  fdatasync(tmpfile);
346  }
347  STOP_TIMER;
348  close(tmpfile);
349 
350 /*
351  * Test fsync
352  */
353  printf(LABEL_FORMAT, "fsync");
354  fflush(stdout);
355 
356  if ((tmpfile = open(filename, O_RDWR | PG_BINARY, 0)) == -1)
357  die("could not open output file");
358  START_TIMER;
359  for (ops = 0; alarm_triggered == false; ops++)
360  {
361  for (writes = 0; writes < writes_per_op; writes++)
362  if (pg_pwrite(tmpfile,
363  buf,
364  XLOG_BLCKSZ,
365  writes * XLOG_BLCKSZ) != XLOG_BLCKSZ)
366  die("write failed");
367  if (fsync(tmpfile) != 0)
368  die("fsync failed");
369  }
370  STOP_TIMER;
371  close(tmpfile);
372 
373 /*
374  * If fsync_writethrough is available, test as well
375  */
376  printf(LABEL_FORMAT, "fsync_writethrough");
377  fflush(stdout);
378 
379 #ifdef HAVE_FSYNC_WRITETHROUGH
380  if ((tmpfile = open(filename, O_RDWR | PG_BINARY, 0)) == -1)
381  die("could not open output file");
382  START_TIMER;
383  for (ops = 0; alarm_triggered == false; ops++)
384  {
385  for (writes = 0; writes < writes_per_op; writes++)
386  if (pg_pwrite(tmpfile,
387  buf,
388  XLOG_BLCKSZ,
389  writes * XLOG_BLCKSZ) != XLOG_BLCKSZ)
390  die("write failed");
391  if (pg_fsync_writethrough(tmpfile) != 0)
392  die("fsync failed");
393  }
394  STOP_TIMER;
395  close(tmpfile);
396 #else
397  printf(NA_FORMAT, _("n/a"));
398 #endif
399 
400 /*
401  * Test open_sync if available
402  */
403  printf(LABEL_FORMAT, "open_sync");
404  fflush(stdout);
405 
406 #ifdef O_SYNC
407  if ((tmpfile = open_direct(filename, O_RDWR | O_SYNC | PG_BINARY, 0)) == -1)
408  {
409  printf(NA_FORMAT, _("n/a*"));
410  fs_warning = true;
411  }
412  else
413  {
414  START_TIMER;
415  for (ops = 0; alarm_triggered == false; ops++)
416  {
417  for (writes = 0; writes < writes_per_op; writes++)
418  if (pg_pwrite(tmpfile,
419  buf,
420  XLOG_BLCKSZ,
421  writes * XLOG_BLCKSZ) != XLOG_BLCKSZ)
422 
423  /*
424  * This can generate write failures if the filesystem has
425  * a large block size, e.g. 4k, and there is no support
426  * for O_DIRECT writes smaller than the file system block
427  * size, e.g. XFS.
428  */
429  die("write failed");
430  }
431  STOP_TIMER;
432  close(tmpfile);
433  }
434 #else
435  printf(NA_FORMAT, _("n/a"));
436 #endif
437 
438  if (fs_warning)
439  {
440  printf(_("* This file system and its mount options do not support direct\n"
441  " I/O, e.g. ext4 in journaled mode.\n"));
442  }
443 }
444 
445 static void
447 {
448  printf(_("\nCompare open_sync with different write sizes:\n"));
449  printf(_("(This is designed to compare the cost of writing 16kB in different write\n"
450  "open_sync sizes.)\n"));
451 
452  test_open_sync(_(" 1 * 16kB open_sync write"), 16);
453  test_open_sync(_(" 2 * 8kB open_sync writes"), 8);
454  test_open_sync(_(" 4 * 4kB open_sync writes"), 4);
455  test_open_sync(_(" 8 * 2kB open_sync writes"), 2);
456  test_open_sync(_("16 * 1kB open_sync writes"), 1);
457 }
458 
459 /*
460  * Test open_sync with different size files
461  */
462 static void
463 test_open_sync(const char *msg, int writes_size)
464 {
465 #ifdef O_SYNC
466  int tmpfile,
467  ops,
468  writes;
469 #endif
470 
471  printf(LABEL_FORMAT, msg);
472  fflush(stdout);
473 
474 #ifdef O_SYNC
475  if ((tmpfile = open_direct(filename, O_RDWR | O_SYNC | PG_BINARY, 0)) == -1)
476  printf(NA_FORMAT, _("n/a*"));
477  else
478  {
479  START_TIMER;
480  for (ops = 0; alarm_triggered == false; ops++)
481  {
482  for (writes = 0; writes < 16 / writes_size; writes++)
483  if (pg_pwrite(tmpfile,
484  buf,
485  writes_size * 1024,
486  writes * writes_size * 1024) !=
487  writes_size * 1024)
488  die("write failed");
489  }
490  STOP_TIMER;
491  close(tmpfile);
492  }
493 #else
494  printf(NA_FORMAT, _("n/a"));
495 #endif
496 }
497 
498 static void
500 {
501  int tmpfile,
502  ops;
503 
504  /*
505  * Test whether fsync can sync data written on a different descriptor for
506  * the same file. This checks the efficiency of multi-process fsyncs
507  * against the same file. Possibly this should be done with writethrough
508  * on platforms which support it.
509  */
510  printf(_("\nTest if fsync on non-write file descriptor is honored:\n"));
511  printf(_("(If the times are similar, fsync() can sync data written on a different\n"
512  "descriptor.)\n"));
513 
514  /*
515  * first write, fsync and close, which is the normal behavior without
516  * multiple descriptors
517  */
518  printf(LABEL_FORMAT, "write, fsync, close");
519  fflush(stdout);
520 
521  START_TIMER;
522  for (ops = 0; alarm_triggered == false; ops++)
523  {
524  if ((tmpfile = open(filename, O_RDWR | PG_BINARY, 0)) == -1)
525  die("could not open output file");
526  if (write(tmpfile, buf, XLOG_BLCKSZ) != XLOG_BLCKSZ)
527  die("write failed");
528  if (fsync(tmpfile) != 0)
529  die("fsync failed");
530  close(tmpfile);
531 
532  /*
533  * open and close the file again to be consistent with the following
534  * test
535  */
536  if ((tmpfile = open(filename, O_RDWR | PG_BINARY, 0)) == -1)
537  die("could not open output file");
538  close(tmpfile);
539  }
540  STOP_TIMER;
541 
542  /*
543  * Now open, write, close, open again and fsync This simulates processes
544  * fsyncing each other's writes.
545  */
546  printf(LABEL_FORMAT, "write, close, fsync");
547  fflush(stdout);
548 
549  START_TIMER;
550  for (ops = 0; alarm_triggered == false; ops++)
551  {
552  if ((tmpfile = open(filename, O_RDWR | PG_BINARY, 0)) == -1)
553  die("could not open output file");
554  if (write(tmpfile, buf, XLOG_BLCKSZ) != XLOG_BLCKSZ)
555  die("write failed");
556  close(tmpfile);
557  /* reopen file */
558  if ((tmpfile = open(filename, O_RDWR | PG_BINARY, 0)) == -1)
559  die("could not open output file");
560  if (fsync(tmpfile) != 0)
561  die("fsync failed");
562  close(tmpfile);
563  }
564  STOP_TIMER;
565 }
566 
567 static void
569 {
570  int tmpfile,
571  ops;
572 
573  /*
574  * Test a simple write without fsync
575  */
576  printf(_("\nNon-sync'ed %dkB writes:\n"), XLOG_BLCKSZ_K);
577  printf(LABEL_FORMAT, "write");
578  fflush(stdout);
579 
580  if ((tmpfile = open(filename, O_RDWR | PG_BINARY, 0)) == -1)
581  die("could not open output file");
582  START_TIMER;
583  for (ops = 0; alarm_triggered == false; ops++)
584  {
585  if (pg_pwrite(tmpfile, buf, XLOG_BLCKSZ, 0) != XLOG_BLCKSZ)
586  die("write failed");
587  }
588  STOP_TIMER;
589  close(tmpfile);
590 }
591 
592 static void
594 {
595  /* Delete the file if it exists. Ignore errors */
596  if (needs_unlink)
597  unlink(filename);
598  /* Finish incomplete line on stdout */
599  puts("");
600  exit(1);
601 }
602 
603 #ifdef HAVE_FSYNC_WRITETHROUGH
604 
605 static int
607 {
608 #ifdef WIN32
609  return _commit(fd);
610 #elif defined(F_FULLFSYNC)
611  return (fcntl(fd, F_FULLFSYNC, 0) == -1) ? -1 : 0;
612 #else
613  errno = ENOSYS;
614  return -1;
615 #endif
616 }
617 #endif
618 
619 /*
620  * print out the writes per second for tests
621  */
622 static void
623 print_elapse(struct timeval start_t, struct timeval stop_t, int ops)
624 {
625  double total_time = (stop_t.tv_sec - start_t.tv_sec) +
626  (stop_t.tv_usec - start_t.tv_usec) * 0.000001;
627  double per_second = ops / total_time;
628  double avg_op_time_us = (total_time / ops) * USECS_SEC;
629 
630  printf(_(OPS_FORMAT), per_second, avg_op_time_us);
631 }
632 
633 #ifndef WIN32
634 static void
636 {
637  alarm_triggered = true;
638 }
639 #else
640 static DWORD WINAPI
641 process_alarm(LPVOID param)
642 {
643  /* WIN32 doesn't support alarm, so we create a thread and sleep here */
644  Sleep(secs_per_test * 1000);
645  alarm_triggered = true;
646  ExitThread(0);
647 }
648 #endif
#define TYPEALIGN(ALIGNVAL, LEN)
Definition: c.h:740
#define ngettext(s, p, n)
Definition: c.h:1165
#define SIGNAL_ARGS
Definition: c.h:1317
#define PG_TEXTDOMAIN(domain)
Definition: c.h:1198
#define PG_BINARY
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int fdatasync(int fildes)
void set_pglocale_pgservice(const char *argv0, const char *app)
Definition: exec.c:460
#define _(x)
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int pg_fsync_writethrough(int fd)
Definition: fd.c:424
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#define required_argument
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#define write(a, b, c)
Definition: win32.h:14
static void const char fflush(stdout)
exit(1)
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Definition: logging.c:83
#define pg_log_error(...)
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#define pg_log_error_hint(...)
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static PgChecksumMode mode
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#define DEFAULT_XLOG_SEG_SIZE
PGDLLIMPORT int optind
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PGDLLIMPORT char * optarg
Definition: getopt.c:52
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Definition: pg_prng.c:201
void pg_prng_seed(pg_prng_state *state, uint64 seed)
Definition: pg_prng.c:83
pg_prng_state pg_global_prng_state
Definition: pg_prng.c:28
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int main(int argc, char *argv[])
Definition: pg_test_fsync.c:99
static char full_buf[DEFAULT_XLOG_SEG_SIZE]
Definition: pg_test_fsync.c:66
static void prepare_buf(void)
static void print_elapse(struct timeval start_t, struct timeval stop_t, int ops)
#define NA_FORMAT
Definition: pg_test_fsync.c:30
static void test_open_syncs(void)
#define FSYNC_FILENAME
Definition: pg_test_fsync.c:25
static char * filename
Definition: pg_test_fsync.c:68
static void handle_args(int argc, char *argv[])
static int open_direct(const char *path, int flags, mode_t mode)
#define START_TIMER
Definition: pg_test_fsync.c:37
#define STOP_TIMER
Definition: pg_test_fsync.c:55
#define LABEL_FORMAT
Definition: pg_test_fsync.c:29
static int needs_unlink
Definition: pg_test_fsync.c:65
static void test_sync(int writes_per_op)
static void test_open(void)
static void test_non_sync(void)
#define die(msg)
Definition: pg_test_fsync.c:95
static char * buf
Definition: pg_test_fsync.c:67
static struct timeval start_t stop_t
Definition: pg_test_fsync.c:69
static void test_open_sync(const char *msg, int writes_size)
static const char * progname
Definition: pg_test_fsync.c:62
static void process_alarm(SIGNAL_ARGS)
static bool alarm_triggered
Definition: pg_test_fsync.c:71
#define USECS_SEC
Definition: pg_test_fsync.c:33
#define OPS_FORMAT
Definition: pg_test_fsync.c:32
static unsigned int secs_per_test
Definition: pg_test_fsync.c:64
#define XLOG_BLCKSZ_K
Definition: pg_test_fsync.c:27
static void signal_cleanup(SIGNAL_ARGS)
#define pg_pwrite
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const char * get_progname(const char *argv0)
Definition: path.c:574
#define printf(...)
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static int fd(const char *x, int i)
Definition: preproc-init.c:105
pqsigfunc pqsignal(int signum, pqsigfunc handler)
Definition: signal.c:197
#define fsync(fd)
Definition: win32_port.h:85
#define SIGHUP
Definition: win32_port.h:176
#define S_IRUSR
Definition: win32_port.h:291
#define SIGALRM
Definition: win32_port.h:182
#define S_IWUSR
Definition: win32_port.h:294
#define O_DSYNC
Definition: win32_port.h:354