time_second vs. time_uptime

Brooks Davis brooks at one-eyed-alien.net
Fri Sep 9 14:48:11 PDT 2005


On Fri, Sep 09, 2005 at 05:44:24PM -0400, Jung-uk Kim wrote:
> If I read the source correctly, time_second can go backwards or 
> forwards when there is a leap second but time_uptime cannot.  Am I 
> right?  If my assumption is right, it seems we have some misuses in 
> kernel, e. g., sched_sync() in sys/kern/vfs_subr.c.  It may not be 
> critical but it worries me a little because a leap second is 
> scheduled to occur at the end of this year. ;-)

Yes, uptime increases monotonically, but leap seconds and adjustments such
as those made by ntpdate will make simple time values jump around.  This
bit me when I first did the interface epochs since absolute times
are not necessarily unique.

-- Brooks

-- 
Any statement of the form "X is the one, true Y" is FALSE.
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