X-Git-Url: https://git.octo.it/?a=blobdiff_plain;f=src%2Frrdtool.c;h=ed1ced1f6547ce87ec698f39b9a986545baa5de4;hb=74525016b183d71f0a5685fa54507078f3f82640;hp=2787944330b28959ec81d8c25a9e9d90d9fe6f23;hpb=fd48357ddeb1b58d5795015e845f3105a7ba3103;p=collectd.git

diff --git a/src/rrdtool.c b/src/rrdtool.c
index 27879443..ed1ced1f 100644
--- a/src/rrdtool.c
+++ b/src/rrdtool.c
@@ -1,6 +1,8 @@
 /**
  * collectd - src/rrdtool.c
  * Copyright (C) 2006-2008  Florian octo Forster
+ * Copyright (C) 2008-2008  Sebastian Harl
+ * Copyright (C) 2009       Mariusz Gronczewski
  *
  * This program is free software; you can redistribute it and/or modify it
  * under the terms of the GNU General Public License as published by the
@@ -17,6 +19,8 @@
  *
  * Authors:
  *   Florian octo Forster <octo at verplant.org>
+ *   Sebastian Harl <sh at tokkee.org>
+ *   Mariusz Gronczewski <xani666 at gmail.com>
  **/
 
 #include "collectd.h"
@@ -40,6 +44,7 @@ struct rrd_cache_s
 	char **values;
 	time_t first_value;
 	time_t last_value;
+	int random_variation;
 	enum
 	{
 		FLAG_NONE   = 0x00,
@@ -105,7 +110,6 @@ 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;
@@ -672,6 +676,7 @@ static int rrd_cache_insert (const char *filename,
 		rc->values = NULL;
 		rc->first_value = 0;
 		rc->last_value = 0;
+		rc->random_variation = 0;
 		rc->flags = FLAG_NONE;
 		new_rc = 1;
 	}
@@ -742,8 +747,7 @@ 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 + (random_timeout - (rand() % random_timeout_mod) ) ) )
+	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! */
@@ -754,6 +758,18 @@ static int rrd_cache_insert (const char *filename,
 			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 +1010,20 @@ 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
 	{