At Thu, 28 Mar 2024 07:09:09 +0000, "Mathew, Cherry G.*" <c%bow.st@localhost> wrote: Subject: Re: timekeeping regression? > > I don't believe FreeBSD has pure PV - so all this seems to point to > SMP + PV and I'm mostly responsible for that. I'm running FreeBSD-14.0 in a PVH domU. In terms of time keeping FreeBSD is using XENTIMER for both its kern.timecounter and its kern.eventtimer (which should be effectively the same as NetBSD does with "xen_system_time"). $ /sbin/sysctl kern.timecounter kern.timecounter.tsc_shift: 1 kern.timecounter.smp_tsc_adjust: 0 kern.timecounter.smp_tsc: 0 kern.timecounter.invariant_tsc: 0 kern.timecounter.fast_gettime: 1 kern.timecounter.tick: 1 kern.timecounter.choice: TSC-low(-100) XENTIMER(950) dummy(-1000000) kern.timecounter.hardware: XENTIMER kern.timecounter.alloweddeviation: 5 kern.timecounter.timehands_count: 2 kern.timecounter.stepwarnings: 0 kern.timecounter.tc.TSC-low.quality: -100 kern.timecounter.tc.TSC-low.frequency: 1579393000 kern.timecounter.tc.TSC-low.counter: 3107614344 kern.timecounter.tc.TSC-low.mask: 4294967295 kern.timecounter.tc.XENTIMER.quality: 950 kern.timecounter.tc.XENTIMER.frequency: 1000000000 kern.timecounter.tc.XENTIMER.counter: 951261480 kern.timecounter.tc.XENTIMER.mask: 4294967295 $ /sbin/sysctl kern.eventtimer kern.eventtimer.choice: XENTIMER(950) LAPIC(100) kern.eventtimer.et.XENTIMER.quality: 950 kern.eventtimer.et.XENTIMER.frequency: 1000000000 kern.eventtimer.et.XENTIMER.flags: 6 kern.eventtimer.et.LAPIC.quality: 100 kern.eventtimer.et.LAPIC.frequency: 0 kern.eventtimer.et.LAPIC.flags: 15 kern.eventtimer.periodic: 0 kern.eventtimer.timer: XENTIMER kern.eventtimer.idletick: 0 kern.eventtimer.singlemul: 4 FreeBSD also uses Xen as the time-of-day clock as well. NetBSD should be doing the same according to the code. -- Greg A. Woods <gwoods%acm.org@localhost> Kelowna, BC +1 250 762-7675 RoboHack <woods%robohack.ca@localhost> Planix, Inc. <woods%planix.com@localhost> Avoncote Farms <woods%avoncote.ca@localhost>
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