Re: Timekeeping hosed by factor 3, high lapic[01] interrupt rates

From: Jens Schweikhardt <schweikh_at_schweikhardt.net>
Date: Fri, 24 Jun 2005 18:50:02 +0200
On Thu, Jun 23, 2005 at 05:14:39PM -0400, John Baldwin wrote:
...
# Ok.  What timecounter does your UP kernel use, and does your UP kernel break 
# if you change the timecounter to i8254?

The UP uses the TSC:
$ sysctl -a|grep timec
kern.timecounter.stepwarnings: 0
kern.timecounter.nbinuptime: 136311
kern.timecounter.nnanouptime: 0
kern.timecounter.nmicrouptime: 664
kern.timecounter.nbintime: 1273
kern.timecounter.nnanotime: 36
kern.timecounter.nmicrotime: 1237
kern.timecounter.ngetbinuptime: 405
kern.timecounter.ngetnanouptime: 29
kern.timecounter.ngetmicrouptime: 2534
kern.timecounter.ngetbintime: 0
kern.timecounter.ngetnanotime: 0
kern.timecounter.ngetmicrotime: 5
kern.timecounter.nsetclock: 2
kern.timecounter.hardware: TSC
kern.timecounter.choice: TSC(800) i8254(0) dummy(-1000000)
kern.timecounter.tick: 1
kern.timecounter.smp_tsc: 0

When I do

$ sysctl kern.timecounter.hardware=i8254

on the UP the time dilation by factor 3 starts and the lapic rate
increases. So yes, that breaks the UP kernel.

Regards,

	Jens
-- 
Jens Schweikhardt http://www.schweikhardt.net/
SIGSIG -- signature too long (core dumped)
Received on Fri Jun 24 2005 - 14:50:25 UTC

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