From cda2f493ee46f6626995236b58af5ac59774f7e0 Mon Sep 17 00:00:00 2001
From: stuart nelson <stuartnelson3@gmail.com>
Date: Sat, 10 Sep 2016 18:55:21 +0200
Subject: [PATCH] wip

---
 collector/cpu_dragonfly.go | 128 +++++++++++++++++++++++++++++++++++++
 1 file changed, 128 insertions(+)
 create mode 100644 collector/cpu_dragonfly.go

diff --git a/collector/cpu_dragonfly.go b/collector/cpu_dragonfly.go
new file mode 100644
index 00000000..fd36418f
--- /dev/null
+++ b/collector/cpu_dragonfly.go
@@ -0,0 +1,128 @@
+// Copyright 2015 The Prometheus Authors
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+// +build !nocpu
+
+package collector
+
+import (
+	"errors"
+	"strconv"
+	"unsafe"
+
+	"github.com/prometheus/client_golang/prometheus"
+)
+
+/*
+#cgo LDFLAGS:
+#include <stdio.h>
+#include <kinfo.h>
+#include <sys/sysctl.h>
+
+int
+getCPUTimes(int *ncpu, double **cpu_times, size_t *cp_times_length)
+{
+	int cpu, mib[2];
+	struct kinfo_cputime cp_t[ncpu];
+	uint64_t user, nice, sys, intr, idle;
+
+	size_t len;
+
+	mib[0] = CTL_HW;
+	mib[1] = HW_NCPU;
+	len = sizeof(*ncpu);
+	if (-1 == sysctl(mib, 2, &ncpu, &len, NULL, 0))
+		return -1;
+
+	bzero(cp_t, sizeof(struct kinfo_cputime)*(*ncpu));
+
+	len = sizeof(cp_t[0])*(*ncpu);
+	if (sysctlbyname("kern.cputime", &cp_t, &len, NULL, 0))
+		return -1;
+
+	// Retrieve clockrate
+	struct clockinfo clockrate;
+	int mib_kern_clockrate[] = {CTL_KERN, KERN_CLOCKRATE};
+	size_t mib_kern_clockrate_len = 2;
+	size_t clockrate_size = sizeof(clockrate);
+
+	if (sysctl(mib_kern_clockrate, mib_kern_clockrate_len, &clockrate, &clockrate_size, NULL, 0) == -1)
+		return -1;
+
+	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) {
+	free(cpu_times);
+}
+*/
+
+import "C"
+
+type statCollector struct {
+	cpu *prometheus.CounterVec
+}
+
+func init() {
+	Factories["cpu"] = NewStatCollector
+}
+
+// Takes a prometheus registry and returns a new Collector exposing
+// CPU stats.
+func NewStatCollector() (Collector, error) {
+	return &statCollector{
+		cpu: prometheus.NewCounterVec(
+			prometheus.CounterOpts{
+				Namespace: Namespace,
+				Name:      "cpu_seconds_total",
+				Help:      "Seconds the CPU spent in each mode.",
+			},
+			[]string{"cpu", "mode"},
+		),
+	}, nil
+}
+
+// Expose CPU stats using sysctl.
+func (c *statCollector) Update(ch chan<- prometheus.Metric) (err error) {
+	// Adapted from
+	// https://www.dragonflybsd.org/mailarchive/users/2010-04/msg00056.html
+
+	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)
+
+	// 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
+}