> On Jun 18, 2021, at 9:18 AM, John Baldwin <j...@freebsd.org> wrote: > > On 6/18/21 7:43 AM, Warner Losh wrote: >> The branch main has been updated by imp: >> URL: >> https://cgit.FreeBSD.org/src/commit/?id=4c0bc591466fd2731ba892269260b7dab74cfbad >> commit 4c0bc591466fd2731ba892269260b7dab74cfbad >> Author: Warner Losh <i...@freebsd.org> >> AuthorDate: 2021-06-18 14:39:42 +0000 >> Commit: Warner Losh <i...@freebsd.org> >> CommitDate: 2021-06-18 14:42:51 +0000 >> man9: add hz(9) and hardclock(9) >> Document aspects of system time keeping. Hz is the nominal rate >> that we >> interrupt the system and is known and the 'tick' period of 1 / hz. >> hardclock is the routine that does various bits of timekeeping. stathz >> and profhz are documented as historical relics that are deprecated >> and replaced by hwpmc.4 and others. >> Reviewed by: phk@, mav@ and gnn@ (previous version) >> Obtained from: hardclock.9 from NetBSD (with FreeBSD >> adjustments) >> Sponsored by: Netflix >> Differential Revision: https://reviews.freebsd.org/D30802 > > The comments about stathz are wrong. While profhz is obsolete and replaced by > hwpmc, statclock is not. statclock is used to implement getrusage(), %CPU in > ps(1), and kern.cp_time (global and per-CPU stats for CPU usage breakdown you > see in top(1) for example). hwpmc doesn't replace any of those. OTOH, it's > also true that there's no real reason for anything outside of the actual timer > code to use stathz (or even profhz) unlike 'hz' which is still used to set > timeout tick values.
Thanks. All that had been blotted out of my mind somehow :(. I’ll update and include you on the review. Warner
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