add tridge's ping_pong.c to the utils folder

Michael

diff --git a/utils/ping_pong/ping_pong.c b/utils/ping_pong/ping_pong.c
new file mode 100644 (file)
index 0000000..8511d95
--- /dev/null
+++ b/utils/ping_pong/ping_pong.c
@@ -0,0 +1,176 @@
+/*
+  this measures the ping-pong byte range lock latency. It is
+  especially useful on a cluster of nodes sharing a common lock
+  manager as it will give some indication of the lock managers
+  performance under stress
+
+  tridge@samba.org, February 2002
+
+*/
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <sys/time.h>
+#include <time.h>
+#include <errno.h>
+#include <string.h>
+#include <unistd.h>
+#include <fcntl.h>
+#include <getopt.h>
+#include <sys/mman.h>
+
+static struct timeval tp1,tp2;
+
+static int do_reads, do_writes, use_mmap;
+
+static void start_timer()
+{
+       gettimeofday(&tp1,NULL);
+}
+
+static double end_timer()
+{
+       gettimeofday(&tp2,NULL);
+       return (tp2.tv_sec + (tp2.tv_usec*1.0e-6)) - 
+               (tp1.tv_sec + (tp1.tv_usec*1.0e-6));
+}
+
+/* lock a byte range in a open file */
+static int lock_range(int fd, int offset, int len)
+{
+       struct flock lock;
+
+       lock.l_type = F_WRLCK;
+       lock.l_whence = SEEK_SET;
+       lock.l_start = offset;
+       lock.l_len = len;
+       lock.l_pid = 0;
+       
+       return fcntl(fd,F_SETLKW,&lock);
+}
+
+/* unlock a byte range in a open file */
+static int unlock_range(int fd, int offset, int len)
+{
+       struct flock lock;
+
+       lock.l_type = F_UNLCK;
+       lock.l_whence = SEEK_SET;
+       lock.l_start = offset;
+       lock.l_len = len;
+       lock.l_pid = 0;
+       
+       return fcntl(fd,F_SETLKW,&lock);
+}
+
+/* run the ping pong test on fd */
+static void ping_pong(int fd, int num_locks)
+{
+       unsigned count = 0;
+       int i=0, loops=0;
+       unsigned char *val;
+       unsigned char incr=0, last_incr=0;
+       unsigned char *p = NULL;
+
+       ftruncate(fd, num_locks+1);
+
+       if (use_mmap) {
+               p = mmap(NULL, num_locks+1, PROT_READ|PROT_WRITE, MAP_SHARED, fd, 0);
+       }
+
+       val = (unsigned char *)calloc(num_locks+1, sizeof(unsigned char));
+
+       start_timer();  
+
+       lock_range(fd, 0, 1);
+       i = 0;
+
+       while (1) {
+               if (lock_range(fd, (i+1) % num_locks, 1) != 0) {
+                       printf("lock at %d failed! - %s\n",
+                              (i+1) % num_locks, strerror(errno));
+               }
+               if (do_reads) {
+                       unsigned char c;
+                       if (use_mmap) {
+                               c = p[i];
+                       } if (pread(fd, &c, 1, i) != 1) {
+                               printf("read failed at %d\n", i);
+                       }
+                       incr = c - val[i];
+                       val[i] = c;
+               }
+               if (do_writes) {
+                       char c = val[i] + 1;
+                       if (use_mmap) {
+                               p[i] = c;
+                       } else if (pwrite(fd, &c, 1, i) != 1) {
+                               printf("write failed at %d\n", i);
+                       }
+               }
+               if (unlock_range(fd, i, 1) != 0) {
+                       printf("unlock at %d failed! - %s\n",
+                              i, strerror(errno));
+               }
+               i = (i+1) % num_locks;
+               count++;
+               if (loops > num_locks && incr != last_incr) {
+                       last_incr = incr;
+                       printf("data increment = %u\n", incr);
+                       fflush(stdout);
+               }
+               if (end_timer() > 1.0) {
+                       printf("%8u locks/sec\r", 
+                              (unsigned)(2*count/end_timer()));
+                       fflush(stdout);
+                       start_timer();
+                       count=0;
+               }
+               loops++;
+       }
+}
+
+int main(int argc, char *argv[])
+{
+       char *fname;
+       int fd, num_locks;
+       int c;
+
+       while ((c = getopt(argc, argv, "rwm")) != -1) {
+               switch (c){
+               case 'w':
+                       do_writes = 1;
+                       break;
+               case 'r':
+                       do_reads = 1;
+                       break;
+               case 'm':
+                       use_mmap = 1;
+                       break;
+               default:
+                       fprintf(stderr, "Unknown option '%c'\n", c);
+                       exit(1);
+               }
+       }
+
+       argv += optind;
+       argc -= optind;
+
+       if (argc < 2) {
+               printf("ping_pong [options] <file> <num_locks>\n");
+               printf("           -r    do reads\n");
+               printf("           -w    do writes\n");
+               printf("           -m    use mmap\n");
+               exit(1);
+       }
+
+       fname = argv[0];
+       num_locks = atoi(argv[1]);
+
+       fd = open(fname, O_CREAT|O_RDWR, 0600);
+       if (fd == -1) exit(1);
+
+       ping_pong(fd, num_locks);
+
+       return 0;
+}