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Use correct frequency for calculating cpu time

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The correct frequency is the systimer frequency,
not the stathz.

From one of the DragonFly developers:

The bump upon each statclock is:
((cur_systimer - prev_systimer) * systimer_freq) >> 32

systimer_freq can be extracted from following
sysctl in userspace:
sysctl kern.cputimer.freq
This commit is contained in:
stuart nelson 2016-09-19 09:35:41 +02:00
parent 8cc06aab04
commit 45ac033d9e
1 changed files with 7 additions and 7 deletions
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14
collector/cpu_dragonfly.go
View file

@ -63,16 +63,16 @@ getCPUTimes(char **cputime) {
return -1; return -1;
} }
// Retrieve clockrate // The bump on each statclock is
struct clockinfo clockrate; // ((cur_systimer - prev_systimer) * systimer_freq) >> 32
size_t clockrate_size = sizeof(clockrate); // where
if (sysctl(mib_kern_clockrate, mib_kern_clockrate_len, &clockrate, &clockrate_size, NULL, 0) == -1 || // systimer_freq = sysctl kern.cputimer.freq
sizeof(clockrate) != clockrate_size) { long freq;
len = sizeof(freq);
if (sysctlbyname("kern.cputimer.freq", &freq, &len, NULL, 0)) {
return -1; return -1;
} }
long freq = clockrate.stathz > 0 ? clockrate.stathz : clockrate.hz;
// Get the cpu times. // Get the cpu times.
struct kinfo_cputime cp_t[ncpu]; struct kinfo_cputime cp_t[ncpu];
bzero(cp_t, sizeof(struct kinfo_cputime)*ncpu); bzero(cp_t, sizeof(struct kinfo_cputime)*ncpu);