* Move NodeCollector into package collector
* Refactor collector enabling
* Update README with new collector enabled flags
* Fix out-of-date inline flag reference syntax
* Use new flags in end-to-end tests
* Add flag to disable all default collectors
* Track if a flag has been set explicitly
* Add --collectors.disable-defaults to README
* Revert disable-defaults flag
* Shorten flags
* Fixup timex collector registration
* Fix end-to-end tests
* Change procfs and sysfs path flags
* Fix review comments
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 removes the requirement to run `node_exporter` as root or with read
access to `/dev/kmem` in order to get CPU usage statistics.
Once FreeBSD adds a macro for the `kern.cp_times` sysctl, the
`setupSysctlMIBs()` function should be replaced by usage of the macro.