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Implement CPU collector on FreeBSD without cgo

This commit is contained in:
Dominik Honnef 2016-12-29 04:26:41 +01:00
parent d2a43f7d05
commit f0adcd163d
1 changed files with 58 additions and 102 deletions
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160
collector/cpu_freebsd.go
View File

@ -16,95 +16,67 @@
package collector package collector
import ( import (
"errors"
"strconv" "strconv"
"unsafe" "unsafe"
"github.com/prometheus/client_golang/prometheus" "github.com/prometheus/client_golang/prometheus"
"golang.org/x/sys/unix"
) )
/* type clockinfo struct {
#cgo LDFLAGS: hz int32 // clock frequency
#include <fcntl.h> tick int32 // micro-seconds per hz tick
#include <stdlib.h> spare int32
#include <sys/param.h> stathz int32 // statistics clock frequency
#include <sys/pcpu.h> profhz int32 // profiling clock frequency
#include <sys/resource.h>
#include <sys/sysctl.h>
#include <sys/time.h>
static int mibs_set_up = 0;
static int mib_kern_cp_times[2];
static size_t mib_kern_cp_times_len = 2;
static const int mib_hw_ncpu[] = {CTL_HW, HW_NCPU};
static const size_t mib_hw_ncpu_len = 2;
static const int mib_kern_clockrate[] = {CTL_KERN, KERN_CLOCKRATE};
static size_t mib_kern_clockrate_len = 2;
// Setup method for MIBs not available as constants.
// Calls to this method must be synchronized externally.
int setupSysctlMIBs() {
int ret = sysctlnametomib("kern.cp_times", mib_kern_cp_times, &mib_kern_cp_times_len);
if (ret == 0) mibs_set_up = 1;
return ret;
} }
int getCPUTimes(int *ncpu, double **cpu_times, size_t *cp_times_length) { type cputime struct {
user float64
// Assert that mibs are set up through setupSysctlMIBs nice float64
if (!mibs_set_up) { sys float64
return -1; intr float64
} idle float64
// Retrieve number of cpu cores
size_t ncpu_size = sizeof(*ncpu);
if (sysctl(mib_hw_ncpu, mib_hw_ncpu_len, ncpu, &ncpu_size, NULL, 0) == -1 ||
sizeof(*ncpu) != ncpu_size) {
return -1;
}
// Retrieve clockrate
struct clockinfo clockrate;
size_t clockrate_size = sizeof(clockrate);
if (sysctl(mib_kern_clockrate, mib_kern_clockrate_len, &clockrate, &clockrate_size, NULL, 0) == -1 ||
sizeof(clockrate) != clockrate_size) {
return -1;
}
// Retrieve cp_times values
*cp_times_length = (*ncpu) * CPUSTATES;
long cp_times[*cp_times_length];
size_t cp_times_size = sizeof(cp_times);
if (sysctl(mib_kern_cp_times, mib_kern_cp_times_len, &cp_times, &cp_times_size, NULL, 0) == -1 ||
sizeof(cp_times) != cp_times_size) {
return -1;
}
// Compute absolute time for different CPU states
long cpufreq = clockrate.stathz > 0 ? clockrate.stathz : clockrate.hz;
*cpu_times = (double *) malloc(sizeof(double)*(*cp_times_length));
for (int i = 0; i < (*cp_times_length); i++) {
(*cpu_times)[i] = ((double) cp_times[i]) / cpufreq;
}
return 0;
} }
void freeCPUTimes(double *cpu_times) { func getCPUTimes() ([]cputime, error) {
free(cpu_times); const states = 5
clockb, err := unix.SysctlRaw("kern.clockrate")
if err != nil {
return nil, err
}
clock := *(*clockinfo)(unsafe.Pointer(&clockb[0]))
cpb, err := unix.SysctlRaw("kern.cp_times")
if err != nil {
return nil, err
}
var cpufreq float64
if clock.stathz > 0 {
cpufreq = float64(clock.stathz)
} else {
cpufreq = float64(clock.hz)
}
var times []float64
for len(cpb) >= int(unsafe.Sizeof(int(0))) {
t := *(*int)(unsafe.Pointer(&cpb[0]))
times = append(times, float64(t)/cpufreq)
cpb = cpb[unsafe.Sizeof(int(0)):]
}
cpus := make([]cputime, len(times)/states)
for i := 0; i < len(times); i += states {
cpu := &cpus[i/states]
cpu.user = times[i]
cpu.nice = times[i+1]
cpu.sys = times[i+2]
cpu.intr = times[i+3]
cpu.idle = times[i+4]
}
return cpus, nil
} }
*/
import "C"
const maxCPUTimesLen = C.MAXCPU * C.CPUSTATES
type statCollector struct { type statCollector struct {
cpu *prometheus.CounterVec cpu *prometheus.CounterVec
} }
@ -116,9 +88,6 @@ func init() {
// Takes a prometheus registry and returns a new Collector exposing // Takes a prometheus registry and returns a new Collector exposing
// CPU stats. // CPU stats.
func NewStatCollector() (Collector, error) { func NewStatCollector() (Collector, error) {
if C.setupSysctlMIBs() == -1 {
return nil, errors.New("could not initialize sysctl MIBs")
}
return &statCollector{ return &statCollector{
cpu: prometheus.NewCounterVec( cpu: prometheus.NewCounterVec(
prometheus.CounterOpts{ prometheus.CounterOpts{
@ -133,7 +102,6 @@ func NewStatCollector() (Collector, error) {
// Expose CPU stats using sysctl. // Expose CPU stats using sysctl.
func (c *statCollector) Update(ch chan<- prometheus.Metric) (err error) { func (c *statCollector) Update(ch chan<- prometheus.Metric) (err error) {
// We want time spent per-cpu per CPUSTATE. // We want time spent per-cpu per CPUSTATE.
// CPUSTATES (number of CPUSTATES) is defined as 5U. // CPUSTATES (number of CPUSTATES) is defined as 5U.
// Order: CP_USER | CP_NICE | CP_SYS | CP_IDLE | CP_INTR // Order: CP_USER | CP_NICE | CP_SYS | CP_IDLE | CP_INTR
@ -145,29 +113,17 @@ func (c *statCollector) Update(ch chan<- prometheus.Metric) (err error) {
// //
// Look into sys/kern/kern_clock.c for details. // Look into sys/kern/kern_clock.c for details.
var ncpu C.int cpuTimes, err := getCPUTimes()
var cpuTimesC *C.double if err != nil {
var cpuTimesLength C.size_t return err
if C.getCPUTimes(&ncpu, &cpuTimesC, &cpuTimesLength) == -1 {
return errors.New("could not retrieve CPU times")
} }
defer C.freeCPUTimes(cpuTimesC) for cpu, t := range cpuTimes {
if cpuTimesLength > maxCPUTimesLen { c.cpu.With(prometheus.Labels{"cpu": strconv.Itoa(cpu), "mode": "user"}).Set(t.user)
return errors.New("more CPU's than MAXCPU?") c.cpu.With(prometheus.Labels{"cpu": strconv.Itoa(cpu), "mode": "nice"}).Set(t.nice)
c.cpu.With(prometheus.Labels{"cpu": strconv.Itoa(cpu), "mode": "system"}).Set(t.sys)
c.cpu.With(prometheus.Labels{"cpu": strconv.Itoa(cpu), "mode": "interrupt"}).Set(t.intr)
c.cpu.With(prometheus.Labels{"cpu": strconv.Itoa(cpu), "mode": "idle"}).Set(t.idle)
} }
// 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) c.cpu.Collect(ch)
return err return err
} }