From: Florian Forster <octo@collectd.org>
Date: Wed, 17 Oct 2012 14:08:07 +0000 (+0200)
Subject: disk plugin: Multiply the average read/write latency with the interval.
X-Git-Tag: collectd-5.0.5~2^2
X-Git-Url: https://git.tokkee.org/?p=collectd.git;a=commitdiff_plain;h=b3c87d5576e385a407081f86c9a3b84fa6983c0f

disk plugin: Multiply the average read/write latency with the interval.

The counter/derive will later be divided by the interval, resulting in too
small rates (for interval > 1.0).

Should fix issue #150. Thanks to Manuel Sanmartin for identifying this problem!
---

diff --git a/src/disk.c b/src/disk.c
index 6187459f..4a78f1bd 100644
--- a/src/disk.c
+++ b/src/disk.c
@@ -235,6 +235,16 @@ static void disk_submit (const char *plugin_instance,
 	plugin_dispatch_values (&vl);
 } /* void disk_submit */
 
+#if KERNEL_LINUX
+static counter_t disk_calc_time_incr (counter_t delta_time, counter_t delta_ops)
+{
+	double avg_time = ((double) delta_time) / ((double) delta_ops);
+	double avg_time_incr = ((double) interval_g) * avg_time;
+
+	return ((counter_t) (avg_time_incr + .5));
+}
+#endif
+
 #if HAVE_IOKIT_IOKITLIB_H
 static signed long long dict_get_value (CFDictionaryRef dict, const char *key)
 {
@@ -579,13 +589,11 @@ static int disk_read (void)
 				diff_write_time = write_time - ds->write_time;
 
 			if (diff_read_ops != 0)
-				ds->avg_read_time += (diff_read_time
-						+ (diff_read_ops / 2))
-					/ diff_read_ops;
+				ds->avg_read_time += disk_calc_time_incr (
+						diff_read_time, diff_read_ops);
 			if (diff_write_ops != 0)
-				ds->avg_write_time += (diff_write_time
-						+ (diff_write_ops / 2))
-					/ diff_write_ops;
+				ds->avg_write_time += disk_calc_time_incr (
+						diff_write_time, diff_write_ops);
 
 			ds->read_ops = read_ops;
 			ds->read_time = read_time;