Date: Tue, 29 Nov 2011 19:34:25 +0100 From: Ireneusz Pluta <ipluta@wp.pl> To: freebsd-questions@freebsd.org Subject: kern.timecounter.hardware change on the fly Message-ID: <4ED525B1.3010100@wp.pl>
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Hi all, is it safe to change kern.timecounter.hardware on a busy production system on the fly? Or I better schedule a downtime to do that? It seems I got a bad current selection, somehow, probably as an effect of leaving /etc/sysctl.conf contents of early experimental setup stage of this machine. $ sysctl -a | grep timecounter kern.timecounter.tick: 1 kern.timecounter.choice: TSC(-100) HPET(900) ACPI-fast(1000) i8254(0) dummy(-1000000) kern.timecounter.hardware: i8254 kern.timecounter.stepwarnings: 0 kern.timecounter.tc.i8254.mask: 65535 kern.timecounter.tc.i8254.counter: 23813 kern.timecounter.tc.i8254.frequency: 1193182 kern.timecounter.tc.i8254.quality: 0 kern.timecounter.tc.ACPI-fast.mask: 16777215 kern.timecounter.tc.ACPI-fast.counter: 4619803 kern.timecounter.tc.ACPI-fast.frequency: 3579545 kern.timecounter.tc.ACPI-fast.quality: 1000 kern.timecounter.tc.HPET.mask: 4294967295 kern.timecounter.tc.HPET.counter: 1703441786 kern.timecounter.tc.HPET.frequency: 14318180 kern.timecounter.tc.HPET.quality: 900 kern.timecounter.tc.TSC.mask: 4294967295 kern.timecounter.tc.TSC.counter: 2720513805 kern.timecounter.tc.TSC.frequency: 2266656152 kern.timecounter.tc.TSC.quality: -100 kern.timecounter.smp_tsc: 0 kern.timecounter.invariant_tsc: 1 This setting seems to affect what is generally described here: http://archives.postgresql.org/pgsql-admin/2011-01/msg00059.php and this is the primary reason I want to change. Should I switch to HPET or ACPI-fast?
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