rrdtool plugin: Optimize away the ‘random_timeout_mod’ variable.

diff --git a/src/rrdtool.c b/src/rrdtool.c
index 2bcfb6d96743076176dc0c96dca3cc60ef9f4c8b..811aea0aa2b13e65155816f600afd2908c6effe7 100644 (file)
--- a/src/rrdtool.c
+++ b/src/rrdtool.c
@@ -106,7 +106,6 @@ static rrdcreate_config_t rrdcreate_config =
 static int         cache_timeout = 0;
 static int         cache_flush_timeout = 0;
 static int         random_timeout = 1;
-static int         random_timeout_mod = 1;
 static time_t      cache_flush_last;
 static c_avl_tree_t *cache = NULL;
 static pthread_mutex_t cache_lock = PTHREAD_MUTEX_INITIALIZER;
@@ -743,17 +742,29 @@ static int rrd_cache_insert (const char *filename,
                        filename, rc->values_num,
                        (unsigned long)(rc->last_value - rc->first_value));
 
-       if ((rc->last_value - rc->first_value + rc->random_variation) >= cache_timeout)
+       if ((rc->last_value + rc->random_variation - rc->first_value) >= cache_timeout)
        {
                /* XXX: If you need to lock both, cache_lock and queue_lock, at
                 * the same time, ALWAYS lock `cache_lock' first! */
                if (rc->flags == FLAG_NONE)
                {
                        int status;
-                       rc->random_variation = (random_timeout - (rand() % random_timeout_mod));
+
                        status = rrd_queue_enqueue (filename, &queue_head, &queue_tail);
                        if (status == 0)
                                rc->flags = FLAG_QUEUED;
+
+                       /* Update the jitter value. Negative values are
+                        * slightly preferred. */
+                       if (random_timeout > 0)
+                       {
+                               rc->random_variation = (rand () % (2 * random_timeout))
+                                       - random_timeout;
+                       }
+                       else
+                       {
+                               rc->random_variation = 0;
+                       }
                }
                else
                {
@@ -994,16 +1005,20 @@ static int rrd_config (const char *key, const char *value)
        }
        else if (strcasecmp ("RandomTimeout", key) == 0)
         {
-               random_timeout = atoi (value);
-               if( random_timeout < 0 )
+               int tmp;
+
+               tmp = atoi (value);
+               if (tmp < 0)
+               {
+                       fprintf (stderr, "rrdtool: `RandomTimeout' must "
+                                       "be greater than or equal to zero.\n");
+                       ERROR ("rrdtool: `RandomTimeout' must "
+                                       "be greater then or equal to zero.");
+               }
+               else
                {
-               fprintf (stderr, "rrdtool: `RandomTimeout' must "
-                        "be greater than or equal to zero.\n");
-               ERROR ("rrdtool: `RandomTimeout' must "
-                      "be greater then or equal to zero.\n");
+                       random_timeout = tmp;
                }
-               else if (random_timeout==0) {random_timeout=1;}
-               else {random_timeout_mod = random_timeout * 2;}
        }
        else
        {