Date: Mon, 22 Nov 2010 09:13:25 +0000 (UTC) From: Colin Percival <cperciva@FreeBSD.org> To: cvs-src-old@freebsd.org Subject: cvs commit: src/sys/kern kern_tc.c Message-ID: <201011220913.oAM9DeBo001605@repoman.freebsd.org>
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cperciva 2010-11-22 09:13:25 UTC
FreeBSD src repository
Modified files:
sys/kern kern_tc.c
Log:
SVN rev 215665 on 2010-11-22 09:13:25Z by cperciva
In tc_windup, handle the case where the previous call to tc_windup was
more than 1s earlier. Prior to this commit, the computation of
th_scale * delta (which produces a 64-bit value equal to the time since
the last tc_windup call in units of 2^(-64) seconds) would overflow and
any complete seconds would be lost.
We fix this by repeatedly converting tc_frequency units of timecounter
to one seconds; this is not exactly correct, since it loses the NTP
adjustment, but if we find ourselves going more than 1s at a time between
clock interrupts, losing a few seconds worth of NTP adjustments is the
least of our problems...
Revision Changes Path
1.195 +10 -0 src/sys/kern/kern_tc.c
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