show lock scaling table

diff --git a/lock_scaling2.c b/lock_scaling2.c
new file mode 100644 (file)
index 0000000..27616b2
--- /dev/null
+++ b/lock_scaling2.c
@@ -0,0 +1,105 @@
+/*
+  demonstrate problem with linear lock lists
+
+  tridge@samba.org, February 2004
+*/
+
+#include <stdio.h>
+#include <fcntl.h>
+#include <unistd.h>
+#include <stdlib.h>
+#include <errno.h>
+#include <string.h>
+#include <signal.h>
+#include <sys/wait.h>
+#include <sys/time.h>
+
+
+static struct timeval tp1,tp2;
+
+static double tvdiff(struct timeval *tv1, struct timeval *tv2)
+{
+       return (tv2->tv_sec + (tv2->tv_usec*1.0e-6)) - 
+               (tv1->tv_sec + (tv1->tv_usec*1.0e-6));
+}
+
+static void start_timer()
+{
+       gettimeofday(&tp1,NULL);
+}
+
+static double end_timer()
+{
+       gettimeofday(&tp2,NULL);
+       fflush(stdout);
+       return tvdiff(&tp1, &tp2);
+}
+
+static int brlock(int fd, off_t offset, int rw_type, int lck_type)
+{
+       struct flock fl;
+       int ret;
+
+       fl.l_type = rw_type;
+       fl.l_whence = SEEK_SET;
+       fl.l_start = offset;
+       fl.l_len = 1;
+       fl.l_pid = 0;
+
+       ret = fcntl(fd,lck_type,&fl);
+
+       if (ret == -1) {
+               printf("brlock failed offset=%d rw_type=%d lck_type=%d : %s\n", 
+                      (int)offset, rw_type, lck_type, strerror(errno));
+       }
+       return 0;
+}
+
+static void setup_locks(int fd, int start, int end)
+{
+       int i;
+       for (i=start;i<end;i++) {
+               brlock(fd, 2*i, F_WRLCK, F_SETLKW);
+       }
+}
+
+
+int main(int argc, char *argv[])
+{
+       int fd;
+       const char *fname = "lock_scaling.dat";
+       int nlocks;
+
+       fd = open(fname, O_RDWR | O_CREAT | O_TRUNC, 0600);
+       if (fd == -1) {
+               perror(fname);
+               exit(1);
+       }
+
+       nlocks = 1;
+
+
+       while (nlocks < 2<<20) {
+               int count=0;
+               double t;
+
+               setup_locks(fd, nlocks/2, nlocks);
+
+               start_timer();
+
+               while (end_timer() < 5.0) {
+                       while ((t=end_timer()) < 1.0) {
+                               brlock(fd, 2*nlocks, F_WRLCK, F_SETLKW);
+                               brlock(fd, 2*nlocks, F_UNLCK, F_SETLKW);
+                               count++;
+                       }
+                       printf("%7d %.1f locks/sec\r", nlocks, count/t);
+                       fflush(stdout);
+               }
+               printf("%7d %8.1f locks/sec\n", nlocks, count/t);
+               nlocks *= 2;
+       }
+
+
+       return 0;
+}