Check BSD's mib which accounts for swap size (#1149)

* Change Dfly's CPU counting frequency, see: https://github.com/prometheus/node_exporter/issues/1129

Signed-off-by: iori-yja <fivio.11235813@gmail.com>

* Convert Dfly's CPU unit into second

Signed-off-by: iori-yja <fivio.11235813@gmail.com>

* Check BSD's mib which accounts for swap size; see #1127

Signed-off-by: iori-yja <fivo.11235813@gmail.com>

* fix swap check code

Signed-off-by: iori-yja <fivo.11235813@gmail.com>

collector/cpu_dragonfly.go

@@ -31,7 +31,7 @@ import (
 #include <stdio.h>
 
 int
-getCPUTimes(uint64_t **cputime, size_t *cpu_times_len, long *freq) {
+getCPUTimes(uint64_t **cputime, size_t *cpu_times_len) {
 	size_t len;
 
 	// Get number of cpu cores.
@@ -44,15 +44,6 @@ getCPUTimes(uint64_t **cputime, size_t *cpu_times_len, long *freq) {
 		return -1;
 	}
 
-	// The bump on each statclock is
-	// ((cur_systimer - prev_systimer) * systimer_freq) >> 32
-	// where
-	// systimer_freq = sysctl kern.cputimer.freq
-	len = sizeof(*freq);
-	if (sysctlbyname("kern.cputimer.freq", freq, &len, NULL, 0)) {
-		return -1;
-	}
-
 	// Get the cpu times.
 	struct kinfo_cputime cp_t[ncpu];
 	bzero(cp_t, sizeof(struct kinfo_cputime)*ncpu);
@@ -103,18 +94,16 @@ func getDragonFlyCPUTimes() ([]float64, error) {
 	// 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
+	// Each value is in microseconds
-	//   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 {
+	if C.getCPUTimes(&cpuTimesC, &cpuTimesLength) == -1 {
 		return nil, errors.New("could not retrieve CPU times")
 	}
 	defer C.free(unsafe.Pointer(cpuTimesC))
@@ -123,7 +112,7 @@ func getDragonFlyCPUTimes() ([]float64, error) {
 
 	cpuTimes := make([]float64, cpuTimesLength)
 	for i, value := range cput {
-		cpuTimes[i] = float64(value) / float64(cpuTimerFreq)
+		cpuTimes[i] = float64(value) / float64(1000000)
 	}
 	return cpuTimes, nil
 }

collector/memory_bsd.go

@@ -45,6 +45,13 @@ func NewMemoryCollector() (Collector, error) {
 	}
 	size := float64(tmp32)
 
+	mibSwapTotal := "vm.swap_total"
+	/* swap_total is FreeBSD specific. Fall back to Dfly specific mib if not present. */
+	_, err = unix.SysctlUint32(mibSwapTotal)
+	if err != nil {
+		mibSwapTotal = "vm.swap_size"
+	}
+
 	fromPage := func(v float64) float64 {
 		return v * size
 	}
@@ -98,7 +105,7 @@ func NewMemoryCollector() (Collector, error) {
 			{
 				name:        "swap_size_bytes",
 				description: "Total swap memory size",
-				mib:         "vm.swap_total",
+				mib:         mibSwapTotal,
 				dataType:    bsdSysctlTypeUint64,
 			},
 			// Descriptions via: top(1)