Random write timeout for rrdtool plugin

[collectd.git] / src / rrdtool.c

diff --git a/src/rrdtool.c b/src/rrdtool.c
index c63f883..2787944 100644 (file)
--- a/src/rrdtool.c
+++ b/src/rrdtool.c
@@ -76,7 +76,8 @@ static const char *config_keys[] =
        "RRARows",
        "RRATimespan",
        "XFF",
-       "WritesPerSecond"
+       "WritesPerSecond",
+       "RandomTimeout"
 };
 static int config_keys_num = STATIC_ARRAY_SIZE (config_keys);
 
@@ -103,6 +104,8 @@ static rrdcreate_config_t rrdcreate_config =
  * ALWAYS lock `cache_lock' first! */
 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;
@@ -739,7 +742,8 @@ 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) >= cache_timeout)
+
+       if ((rc->last_value - rc->first_value) >= (cache_timeout + (random_timeout - (rand() % random_timeout_mod) ) ) )
        {
                /* XXX: If you need to lock both, cache_lock and queue_lock, at
                 * the same time, ALWAYS lock `cache_lock' first! */
@@ -988,6 +992,19 @@ static int rrd_config (const char *key, const char *value)
                        write_rate = 1.0 / wps;
                }
        }
+       else if (strcasecmp ("RandomTimeout", key) == 0)
+        {
+               random_timeout = atoi (value);
+               if( random_timeout < 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.\n");
+               }
+               else if (random_timeout==0) {random_timeout=1;}
+               else {random_timeout_mod = random_timeout * 2;}
+       }
        else
        {
                return (-1);