Simplify test_fsync duration computation.

diff --git a/src/tools/fsync/test_fsync.c b/src/tools/fsync/test_fsync.c
index 8a258fe7172476acd0b6cc86035bac37ed8b7732..79299152826a02d5b59cdccc6397b8982233e179 100644 (file)
--- a/src/tools/fsync/test_fsync.c
+++ b/src/tools/fsync/test_fsync.c
@@ -1,5 +1,5 @@
 /*
- * $PostgreSQL: pgsql/src/tools/fsync/test_fsync.c,v 1.28 2010/07/04 01:50:29 momjian Exp $
+ * $PostgreSQL: pgsql/src/tools/fsync/test_fsync.c,v 1.29 2010/07/04 13:42:51 momjian Exp $
  *
  *
  *     test_fsync.c
@@ -79,7 +79,7 @@ main(int argc, char *argv[])
        /*
         * Simple write
         */
-       printf("Simple write timing:\n");
+       printf("Simple write:\n");
        /* write only */
        gettimeofday(&start_t, NULL);
        for (i = 0; i < loops; i++)
@@ -271,7 +271,7 @@ main(int argc, char *argv[])
        /*
         * Compare 1 to 2 writes
         */
-       printf("\nCompare open_sync sizes:\n");
+       printf("\nCompare open_sync with different sizes:\n");
 
 #ifdef OPEN_SYNC_FLAG
        /* 16k open_sync write */
@@ -368,17 +368,10 @@ main(int argc, char *argv[])
 void
 print_elapse(struct timeval start_t, struct timeval stop_t)
 {
-       double total_time, per_second;
-
-       if (stop_t.tv_usec < start_t.tv_usec)
-       {
-               stop_t.tv_sec--;
-               stop_t.tv_usec += 1000000;
-       }
-
-       total_time = (stop_t.tv_sec - start_t.tv_sec) +
+       double total_time = (stop_t.tv_sec - start_t.tv_sec) +
+       /* usec subtraction might be negative, e.g. 5.4 - 4.8 */
                                 (stop_t.tv_usec - start_t.tv_usec) * 0.000001;
-       per_second = loops / total_time;
+       double per_second = loops / total_time;
        
        printf("%9.3f/second\n", per_second);
 }