Write better timing code for trylock. Refs #1738.

git-svn-id: file:///svn/toku/tokudb@11672 c7de825b-a66e-492c-adef-691d508d4ae1

newbrt/locking-benchmarks/Makefile

-CFLAGS=-O2 -Wall -W -Werror -D_GNU_SOURCE
+CPPFLAGS= -D_GNU_SOURCE -I../../toku_include
+CFLAGS=-O2 -Wall -W -Werror
 LDFLAGS=-lpthread
-trylock: 
+default: trylock trylock-rdtsc mfence-benchmark process_locks pthread-locks

newbrt/locking-benchmarks/mfence-benchmark.c

@@ -107,7 +107,7 @@ int main (int argc __attribute__((__unused__)),
 	  char *argv[] __attribute__((__unused__))) {
     int x[4];
     int i;
-    for (i=0; i<2; i++) {
+    for (i=0; i<4; i++) {
 	do1(x);
 	domfence(x);
 	dosfence(x);

newbrt/locking-benchmarks/trylock-rdtsc.c

+/* Like trylock, except use rdstc */
+#define _MULTI_THREADED
+#include <pthread.h>
+#include <stdio.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <errno.h>
+#include <sys/time.h>
+#include <unistd.h>
+#include <rdtsc.h>
+
+float tdiff (struct timeval *start, struct timeval *end) {
+    return 1e6*(end->tv_sec-start->tv_sec) +(end->tv_usec - start->tv_usec);
+}
+
+unsigned long long rtdiff (unsigned long long a, unsigned long long b) {
+    return (b-a);
+}
+
+/* Simple function to check the return code and exit the program
+   if the function call failed
+   */
+static void compResults(char *string, int rc) {
+  if (rc) {
+    printf("Error on : %s, rc=%d",
+           string, rc);
+    exit(EXIT_FAILURE);
+  }
+  return;
+}
+
+pthread_rwlock_t       rwlock = PTHREAD_RWLOCK_INITIALIZER;
+
+void *rdlockThread(void *arg __attribute__((unused)))
+{
+  int             rc;
+  int             count=0;
+
+  unsigned long long t_start, t_end;
+
+  printf("Entered thread, getting read lock with mp wait\n");
+  Retry:
+
+  t_start = rdtsc();
+  rc = pthread_rwlock_tryrdlock(&rwlock);
+  t_end = rdtsc();
+  printf("pthread_rwlock_tryrdlock took %llu clocks\n", rtdiff(t_start,t_end));
+  if (rc == EBUSY) {
+    if (count >= 10) {
+      printf("Retried too many times, failure!\n");
+
+      exit(EXIT_FAILURE);
+    }
+    ++count;
+    printf("Could not get lock, do other work, then RETRY...\n");
+    sleep(1);
+    goto Retry;
+  }
+  compResults("pthread_rwlock_tryrdlock() 1\n", rc);
+
+  sleep(2);
+
+  printf("unlock the read lock\n");
+  t_start = rdtsc();
+  rc = pthread_rwlock_unlock(&rwlock);
+  t_end = rdtsc();
+  compResults("pthread_rwlock_unlock()\n", rc);
+  printf("%llu to %llu is %llu clocks\n", t_start, t_end, rtdiff(t_start, t_end));
+
+  printf("Secondary thread complete\n");
+  return NULL;
+}
+
+int main(int argc __attribute__((unused)), char **argv)
+{
+  int                   rc=0;
+  pthread_t             thread;
+  unsigned long long t_start, t_end;
+
+  printf("Enter Testcase - %s\n", argv[0]);
+
+  t_start = rdtsc();
+  t_end   = rdtsc();
+  printf("nop Took %llu clocks\n", rtdiff(t_start, t_end));
+
+  {
+      int N=1000;
+      int i;
+      printf("Main, get and release the write lock %d times\n", N);
+      t_start = rdtsc();
+      for (i=0; i<N; i++) {
+	  rc = pthread_rwlock_wrlock(&rwlock);
+	  rc = pthread_rwlock_unlock(&rwlock);
+      }
+      t_end = rdtsc();
+      compResults("pthread_rwlock_wrlock()\n", rc);
+      printf("Took %5.2f clocks/op\n", ((double)(t_end-t_start))/N);
+  }
+
+  printf("Main, get the write lock\n");
+  t_start = rdtsc();
+  rc = pthread_rwlock_wrlock(&rwlock);
+  t_end   = rdtsc();
+  compResults("pthread_rwlock_wrlock()\n", rc);
+  printf("Took %llu clocks\n", rtdiff(t_start, t_end));
+
+  printf("Main, create the try read lock thread\n");
+  rc = pthread_create(&thread, NULL, rdlockThread, NULL);
+  compResults("pthread_create\n", rc);
+
+  printf("Main, wait a bit holding the write lock\n");
+  sleep(5);
+
+  printf("Main, Now unlock the write lock\n");
+  t_start = rdtsc();
+  rc = pthread_rwlock_unlock(&rwlock);
+  t_end   = rdtsc();
+  compResults("pthread_rwlock_unlock()\n", rc);
+  printf("Took %llu clocks\n", rtdiff(t_start, t_end));
+
+  printf("Main, wait for the thread to end\n");
+  rc = pthread_join(thread, NULL);
+  compResults("pthread_join\n", rc);
+
+  rc = pthread_rwlock_destroy(&rwlock);
+  compResults("pthread_rwlock_destroy()\n", rc);
+  printf("Main completed\n");
+  return 0;
+}