[collectd] cpu module and saving jiffies / OpenBSD

[Michael Stapelberg]

Hi,

I'm using collectd on OpenBSD (previously on linux) and I noticed that the cpu
plugin saves broken values. That is, my CPU would be idle 126% ;-).

I'm not sure how you accomplish putting jiffies (from /proc/stat) to rrdtool
and getting percentage values in the file actually... I tried writing a proof
of concept but it didn't work, it'd be nice if you enlighten me.

Anyway, as the CPU stats are collected on OpenBSD using libstatgrab which also
support percentages, I changed the cpu-rrd-files to use GAUGE and cpu.c to
submit a gauge_t. Now the values are accurate. I wonder why this is not by
default a GAUGE? Are there any reasons or should we change it? Patch file for
the libstatgrab-part is attached.

Best regards,
Michael
-------------- next part --------------
diff --git a/cpu.c b/cpu.c
index e9ab783..25f038e 100644
--- a/cpu.c
+++ b/cpu.c
@@ -170,12 +170,12 @@ static int init (void)
 	return (0);
 } /* int init */
 
-static void submit (int cpu_num, const char *type_instance, counter_t value)
+static void submit (int cpu_num, const char *type_instance, gauge_t gauge)
 {
 	value_t values[1];
 	value_list_t vl = VALUE_LIST_INIT;
 
-	values[0].counter = value;
+	values[0].gauge = gauge;
 
 	vl.values = values;
 	vl.values_len = 1;
@@ -386,21 +386,21 @@ static int cpu_read (void)
 /* #endif HAVE_SYSCTLBYNAME */
 
 #elif defined(HAVE_LIBSTATGRAB)
-       sg_cpu_stats *cs;
-       cs = sg_get_cpu_stats ();
+       sg_cpu_percents *cs;
+       cs = sg_get_cpu_percents ();
 
        if (cs == NULL)
        {
-	       ERROR ("cpu plugin: sg_get_cpu_stats failed.");
+	       ERROR ("cpu plugin: sg_get_cpu_percents failed.");
                return (-1);
        }
 
-       submit (0, "idle",   (counter_t) cs->idle);
-       submit (0, "nice",   (counter_t) cs->nice);
-       submit (0, "swap",   (counter_t) cs->swap);
-       submit (0, "system", (counter_t) cs->kernel);
-       submit (0, "user",   (counter_t) cs->user);
-       submit (0, "wait",   (counter_t) cs->iowait);
+       submit (0, "idle",   (gauge_t) cs->idle);
+       submit (0, "nice",   (gauge_t) cs->nice);
+       submit (0, "swap",   (gauge_t) cs->swap);
+       submit (0, "system", (gauge_t) cs->kernel);
+       submit (0, "user",   (gauge_t) cs->user);
+       submit (0, "wait",   (gauge_t) cs->iowait);
 #endif /* HAVE_LIBSTATGRAB */
 
 	return (0);
-------------- next part --------------
diff --git a/types.db b/types.db
index 9d814ad..673684d 100644
--- a/types.db
+++ b/types.db
@@ -9,7 +9,7 @@ charge			value:GAUGE:0:U
 connections		value:COUNTER:0:U
 counter			value:COUNTER:U:U
 cpufreq			value:GAUGE:0:U
-cpu                     value:COUNTER:0:4294967295
+cpu                     value:GAUGE:0:100
 current			value:GAUGE:U:U
 delay			seconds:GAUGE:-1000000:1000000
 df			used:GAUGE:0:1125899906842623, free:GAUGE:0:1125899906842623