ctdb/utils/ping_pong/ping_pong.c

   1 /*
   2    A ping-pong fcntl byte range lock test
   3
   4    Copyright (C) Andrew Tridgell 2002
   5    Copyright (C) Michael Adam 2012
   6
   7    This program is free software; you can redistribute it and/or modify
   8    it under the terms of the GNU General Public License as published by
   9    the Free Software Foundation; either version 3 of the License, or
  10    (at your option) any later version.
  11
  12    This program is distributed in the hope that it will be useful,
  13    but WITHOUT ANY WARRANTY; without even the implied warranty of
  14    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15    GNU General Public License for more details.
  16
  17    You should have received a copy of the GNU General Public License
  18    along with this program; if not, see <http://www.gnu.org/licenses/>.
  19 */
  20
  21 /*
  22   This measures the ping-pong byte range lock latency. It is
  23   especially useful on a cluster of nodes sharing a common lock
  24   manager as it will give some indication of the lock managers
  25   performance under stress.
  26
  27   tridge@samba.org, February 2002
  28
  29 */
  30
  31 #define _XOPEN_SOURCE 500
  32
  33 #include <stdio.h>
  34 #include <stdlib.h>
  35 #include <sys/time.h>
  36 #include <time.h>
  37 #include <errno.h>
  38 #include <string.h>
  39 #include <unistd.h>
  40 #include <fcntl.h>
  41 #include <sys/mman.h>
  42
  43 static struct timeval tp1,tp2;
  44
  45 static int do_reads, do_writes, use_mmap, do_check;
  46
  47 static void start_timer(void)
  48 {
  49         gettimeofday(&tp1,NULL);
  50 }
  51
  52 static double end_timer(void)
  53 {
  54         gettimeofday(&tp2,NULL);
  55         return (tp2.tv_sec + (tp2.tv_usec*1.0e-6)) -
  56                 (tp1.tv_sec + (tp1.tv_usec*1.0e-6));
  57 }
  58
  59 /* lock a byte range in a open file */
  60 static int lock_range(int fd, int offset, int len)
  61 {
  62         struct flock lock;
  63
  64         lock.l_type = F_WRLCK;
  65         lock.l_whence = SEEK_SET;
  66         lock.l_start = offset;
  67         lock.l_len = len;
  68         lock.l_pid = 0;
  69
  70         return fcntl(fd,F_SETLKW,&lock);
  71 }
  72
  73 /* check whether we could place a lock */
  74 int check_lock(int fd, int offset, int len)
  75 {
  76         struct flock lock;
  77         int ret;
  78
  79         lock.l_type = F_WRLCK;
  80         lock.l_whence = SEEK_SET;
  81         lock.l_start = offset;
  82         lock.l_len = len;
  83         lock.l_pid = 0;
  84
  85         ret = fcntl(fd, F_GETLK, &lock);
  86         if (ret != 0) {
  87                 printf("error calling fcntl F_GETLCK: %s\n", strerror(errno));
  88                 return -1;
  89         }
  90
  91         if (lock.l_type == F_UNLCK) {
  92                 /* we would be able to place the lock */
  93                 return 0;
  94         }
  95
  96         /* we would not be able to place lock */
  97         printf("check_lock failed: lock held: "
  98                "pid='%d', type='%d', start='%d', len='%d'\n",
  99                (int)lock.l_pid, (int)lock.l_type, (int)lock.l_start, (int)lock.l_len);
 100         return 1;
 101 }
 102
 103 /* unlock a byte range in a open file */
 104 static int unlock_range(int fd, int offset, int len)
 105 {
 106         struct flock lock;
 107
 108         lock.l_type = F_UNLCK;
 109         lock.l_whence = SEEK_SET;
 110         lock.l_start = offset;
 111         lock.l_len = len;
 112         lock.l_pid = 0;
 113
 114         return fcntl(fd,F_SETLKW,&lock);
 115 }
 116
 117 /* run the ping pong test on fd */
 118 static void ping_pong(int fd, int num_locks)
 119 {
 120         unsigned count = 0;
 121         int i=0, loops=0;
 122         unsigned char *val;
 123         unsigned char incr=0, last_incr=0;
 124         unsigned char *p = NULL;
 125         int ret;
 126
 127         ret = ftruncate(fd, num_locks+1);
 128         if (ret == -1) {
 129                 printf("ftruncate failed: %s\n", strerror(errno));
 130                 return;
 131         }
 132
 133         if (use_mmap) {
 134                 p = mmap(NULL, num_locks+1, PROT_READ|PROT_WRITE, MAP_SHARED, fd, 0);
 135                 if (p == MAP_FAILED) {
 136                         printf("mmap failed: %s\n", strerror(errno));
 137                         return;
 138                 }
 139         }
 140
 141         val = (unsigned char *)calloc(num_locks+1, sizeof(unsigned char));
 142         if (val == NULL) {
 143                 printf("calloc failed\n");
 144                 return;
 145         }
 146
 147         start_timer();
 148
 149         lock_range(fd, 0, 1);
 150         i = 0;
 151
 152         while (1) {
 153                 if (lock_range(fd, (i+1) % num_locks, 1) != 0) {
 154                         printf("lock at %d failed! - %s\n",
 155                                (i+1) % num_locks, strerror(errno));
 156                 }
 157                 if (do_check) {
 158                         ret = check_lock(fd, i, 1);
 159                 }
 160                 if (do_reads) {
 161                         unsigned char c;
 162                         if (use_mmap) {
 163                                 c = p[i];
 164                         } else if (pread(fd, &c, 1, i) != 1) {
 165                                 printf("read failed at %d\n", i);
 166                         }
 167                         incr = c - val[i];
 168                         val[i] = c;
 169                 }
 170                 if (do_writes) {
 171                         char c = val[i] + 1;
 172                         if (use_mmap) {
 173                                 p[i] = c;
 174                         } else if (pwrite(fd, &c, 1, i) != 1) {
 175                                 printf("write failed at %d\n", i);
 176                         }
 177                 }
 178                 if (unlock_range(fd, i, 1) != 0) {
 179                         printf("unlock at %d failed! - %s\n",
 180                                i, strerror(errno));
 181                 }
 182                 i = (i+1) % num_locks;
 183                 count++;
 184                 if (loops > num_locks && incr != last_incr) {
 185                         last_incr = incr;
 186                         printf("data increment = %u\n", incr);
 187                         fflush(stdout);
 188                 }
 189                 if (end_timer() > 1.0) {
 190                         printf("%8u locks/sec\r",
 191                                (unsigned)(2*count/end_timer()));
 192                         fflush(stdout);
 193                         start_timer();
 194                         count=0;
 195                 }
 196                 loops++;
 197         }
 198 }
 199
 200 int main(int argc, char *argv[])
 201 {
 202         char *fname;
 203         int fd, num_locks;
 204         int c;
 205
 206         while ((c = getopt(argc, argv, "rwmc")) != -1) {
 207                 switch (c){
 208                 case 'w':
 209                         do_writes = 1;
 210                         break;
 211                 case 'r':
 212                         do_reads = 1;
 213                         break;
 214                 case 'm':
 215                         use_mmap = 1;
 216                         break;
 217                 case 'c':
 218                         do_check = 1;
 219                         break;
 220                 default:
 221                         fprintf(stderr, "Unknown option '%c'\n", c);
 222                         exit(1);
 223                 }
 224         }
 225
 226         argv += optind;
 227         argc -= optind;
 228
 229         if (argc < 2) {
 230                 printf("ping_pong [options] <file> <num_locks>\n");
 231                 printf("           -r    do reads\n");
 232                 printf("           -w    do writes\n");
 233                 printf("           -m    use mmap\n");
 234                 printf("           -c    check locks\n");
 235                 exit(1);
 236         }
 237
 238         fname = argv[0];
 239         num_locks = atoi(argv[1]);
 240         if (num_locks <= 0) {
 241                 printf("num_locks should be > 0\n");
 242                 exit(1);
 243         }
 244
 245         fd = open(fname, O_CREAT|O_RDWR, 0600);
 246         if (fd == -1) exit(1);
 247
 248         ping_pong(fd, num_locks);
 249
 250         return 0;
 251 }