converted freebsd cpu metrics to seconds

1 files changed, 43 insertions, 5 deletions

diff --git a/collector/cpu_freebsd.go b/collector/cpu_freebsd.go
index aa02c1a..a04007a 100644
--- a/collector/cpu_freebsd.go
+++ b/collector/cpu_freebsd.go
@@ -28,9 +28,26 @@ import (
 #cgo LDFLAGS: -lkvm
 #include <fcntl.h>
 #include <kvm.h>
+#include <stdlib.h>
 #include <sys/param.h>
 #include <sys/pcpu.h>
 #include <sys/resource.h>
+#include <sys/sysctl.h>
+#include <sys/time.h>
+
+long _clockrate() {
+        struct clockinfo clockrate;
+        size_t size = sizeof(clockrate);
+        int res = sysctlbyname("kern.clockrate", &clockrate, &size, NULL, 0);
+        if (res == -1) {
+                return -1;
+        }
+        if (size != sizeof(clockrate)) {
+                return -2;
+        }
+        return clockrate.stathz > 0 ? clockrate.stathz : clockrate.hz;
+}
+
 */
 import "C"
 
@@ -70,16 +87,37 @@ func (c *statCollector) Update(ch chan<- prometheus.Metric) (err error) {
         }
         defer C.kvm_close(kd)
 
+        // The cp_time variable is an array of CPUSTATES long integers -- in
+        // the same format as the kern.cp_time sysctl.  According to the
+        // comments in sys/kern/kern_clock.c, the frequency of this timer will
+        // be stathz (or hz, if stathz is zero).
+        clockrate, err := getClockRate()
+        if err != nil {
+                return err
+        }
+
         ncpus := C.kvm_getncpus(kd)
         for i := 0; i < int(ncpus); i++ {
                 pcpu := C.kvm_getpcpu(kd, C.int(i))
                 cp_time := ((*C.struct_pcpu)(unsafe.Pointer(pcpu))).pc_cp_time
-                c.cpu.With(prometheus.Labels{"cpu": strconv.Itoa(i), "mode": "user"}).Set(float64(cp_time[C.CP_USER]))
-                c.cpu.With(prometheus.Labels{"cpu": strconv.Itoa(i), "mode": "nice"}).Set(float64(cp_time[C.CP_NICE]))
-                c.cpu.With(prometheus.Labels{"cpu": strconv.Itoa(i), "mode": "system"}).Set(float64(cp_time[C.CP_SYS]))
-                c.cpu.With(prometheus.Labels{"cpu": strconv.Itoa(i), "mode": "interrupt"}).Set(float64(cp_time[C.CP_INTR]))
-                c.cpu.With(prometheus.Labels{"cpu": strconv.Itoa(i), "mode": "idle"}).Set(float64(cp_time[C.CP_IDLE]))
+                c.cpu.With(prometheus.Labels{"cpu": strconv.Itoa(i), "mode": "user"}).Set(float64(cp_time[C.CP_USER])/clockrate)
+                c.cpu.With(prometheus.Labels{"cpu": strconv.Itoa(i), "mode": "nice"}).Set(float64(cp_time[C.CP_NICE])/clockrate)
+                c.cpu.With(prometheus.Labels{"cpu": strconv.Itoa(i), "mode": "system"}).Set(float64(cp_time[C.CP_SYS])/clockrate)
+                c.cpu.With(prometheus.Labels{"cpu": strconv.Itoa(i), "mode": "interrupt"}).Set(float64(cp_time[C.CP_INTR])/clockrate)
+                c.cpu.With(prometheus.Labels{"cpu": strconv.Itoa(i), "mode": "idle"}).Set(float64(cp_time[C.CP_IDLE])/clockrate)
         }
         c.cpu.Collect(ch)
         return err
 }
+
+func getClockRate() (float64, error) {
+        clockrate := C._clockrate()
+        if clockrate == -1 {
+                return 0, errors.New("sysctl(kern.clockrate) failed")
+        } else if clockrate == -2 {
+                return 0, errors.New("sysctl(kern.clockrate) failed, wrong buffer size")
+        } else if clockrate <= 0 {
+                return 0, errors.New("sysctl(kern.clockrate) bad clocktime")
+        }
+        return float64(clockrate), nil
+}