Update cpu collector for OpenBSD 6.4 (prometheus#1094)

Starting with (not yet released) OpenBSD 6.4, sysctl KERN_CPTIME2 will return ENODEV for offline CPUs. SMT siblings are reported as offline when hw.smt is disabled, which is the default since one of the later Spectre variants. So this might affect a few systems. For more details see: https://cvsweb.openbsd.org/src/sys/kern/kern_sysctl.c#rev1.348 Signed-off-by: Ralf Horstmann <[email protected]>
ii · Oct 2, 2018 · 9f820bd · 9f820bd
1 parent 5a461d2
commit 9f820bd
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diff --git a/CHANGELOG.md b/CHANGELOG.md
@@ -24,6 +24,7 @@ Darwin meminfo metrics have been renamed to match Prometheus conventions. #1060
 * [BUGFIX] Handle vanishing PIDs #1043
 * [BUGFIX] Correctly cast Darwin memory info #1060
 * [BUGFIX] Filter systemd units in Go for compatibility with older versions #1083
+* [BUGFIX] Update cpu collector for OpenBSD 6.4
 
 ## 0.16.0 / 2018-05-15
 

diff --git a/collector/cpu_openbsd.go b/collector/cpu_openbsd.go
@@ -59,10 +59,12 @@ func (c *cpuCollector) Update(ch chan<- prometheus.Metric) (err error) {
 	var cp_time [][C.CPUSTATES]C.int64_t
 	for i := 0; i < int(ncpus); i++ {
 		cp_timeb, err := unix.SysctlRaw("kern.cp_time2", i)
-		if err != nil {
+		if err != nil && err != unix.ENODEV {
 			return err
 		}
-		cp_time = append(cp_time, *(*[C.CPUSTATES]C.int64_t)(unsafe.Pointer(&cp_timeb[0])))
+		if err != unix.ENODEV {
+			cp_time = append(cp_time, *(*[C.CPUSTATES]C.int64_t)(unsafe.Pointer(&cp_timeb[0])))
+		}
 	}
 
 	for cpu, time := range cp_time {