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From: Bruce Evans <bde@FreeBSD.ORG>
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Date: Tue, 24 Feb 1998 20:10:33 -0800 (PST)
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To: cvs-committers@FreeBSD.ORG, cvs-all@FreeBSD.ORG, cvs-sys@FreeBSD.ORG
Subject: cvs commit: src/sys/kern kern_time.c
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bde         1998/02/24 20:10:33 PST

  Modified files:
    sys/kern             kern_time.c 
  Log:
  Fixed the calculation of `delta' in settime().  We once set all
  times consistently wrong (up to 1 tick too late), but recent changes
  fixed the setting of the main clock, making other times inconsistent.
  The inconsistencies tended to show up as a negative resource usage
  for the process that set the time.
  
  Fixed the check for setting the clock backwards.  A stale timestamp
  (`time') was checked, so it was possible to set the clock backwards
  by up to almost 1 tick.  Until recently, this bug was compensated
  for by setting the clock consistently wrong.
  
  Merged the comment about setting the clock backwards from Lite2.
  
  Removed latency micro-optimizations/speed pessimizations in settime().
  microtime() and set_timecounter() are relatively expensive, and
  they must be called together with clock updates blocked to get a
  consistent `delta', so significant latency optimizations are not
  possible.
  
  Removed some stale comments.
  
  Revision  Changes    Path
  1.42      +14 -29    src/sys/kern/kern_time.c