func getDragonFlyCPUTimes() ([]float64, error) {
// We want time spent per-cpu per CPUSTATE.
// CPUSTATES (number of CPUSTATES) is defined as 5U.
// States: CP_USER | CP_NICE | CP_SYS | CP_IDLE | CP_INTR
//
// Each value is a counter incremented at frequency
// kern.cputimer.freq
//
// Look into sys/kern/kern_clock.c for details.
var (
cpuTimesC *C.uint64_t
cpuTimerFreq C.long
cpuTimesLength C.size_t
)
if C.getCPUTimes(&cpuTimesC, &cpuTimesLength, &cpuTimerFreq) == -1 {
return nil, errors.New("could not retrieve CPU times")
}
defer C.free(unsafe.Pointer(cpuTimesC))
cput := (*[maxCPUTimesLen]C.uint64_t)(unsafe.Pointer(cpuTimesC))[:cpuTimesLength:cpuTimesLength]
cpuTimes := make([]float64, cpuTimesLength)
for i, value := range cput {
cpuTimes[i] = float64(value) / float64(cpuTimerFreq)
}
return cpuTimes, nil
}
// Expose CPU stats using sysctl.
func (c *statCollector) Update(ch chan<- prometheus.Metric) (err error) {
// We want time spent per-cpu per CPUSTATE.
// CPUSTATES (number of CPUSTATES) is defined as 5U.
// Order: CP_USER | CP_NICE | CP_SYS | CP_IDLE | CP_INTR
// sysctl kern.cp_times provides hw.ncpu * CPUSTATES long integers:
// hw.ncpu * (space-separated list of the above variables)
//
// Each value is a counter incremented at frequency
// kern.clockrate.(stathz | hz)
//
// Look into sys/kern/kern_clock.c for details.
var ncpu C.int
var cpuTimesC *C.double
var cpuTimesLength C.size_t
if C.getCPUTimes(&ncpu, &cpuTimesC, &cpuTimesLength) == -1 {
return errors.New("could not retrieve CPU times")
}
defer C.freeCPUTimes(cpuTimesC)
if cpuTimesLength > maxCPUTimesLen {
return errors.New("more CPU's than MAXCPU?")
}
// Convert C.double array to Go array (https://github.com/golang/go/wiki/cgo#turning-c-arrays-into-go-slices).
cpuTimes := (*[maxCPUTimesLen]C.double)(unsafe.Pointer(cpuTimesC))[:cpuTimesLength:cpuTimesLength]
for cpu := 0; cpu < int(ncpu); cpu++ {
base_idx := C.CPUSTATES * cpu
c.cpu.With(prometheus.Labels{"cpu": strconv.Itoa(cpu), "mode": "user"}).Set(float64(cpuTimes[base_idx+C.CP_USER]))
c.cpu.With(prometheus.Labels{"cpu": strconv.Itoa(cpu), "mode": "nice"}).Set(float64(cpuTimes[base_idx+C.CP_NICE]))
c.cpu.With(prometheus.Labels{"cpu": strconv.Itoa(cpu), "mode": "system"}).Set(float64(cpuTimes[base_idx+C.CP_SYS]))
c.cpu.With(prometheus.Labels{"cpu": strconv.Itoa(cpu), "mode": "interrupt"}).Set(float64(cpuTimes[base_idx+C.CP_INTR]))
c.cpu.With(prometheus.Labels{"cpu": strconv.Itoa(cpu), "mode": "idle"}).Set(float64(cpuTimes[base_idx+C.CP_IDLE]))
}
c.cpu.Collect(ch)
return err
}