Commit 9acf6597 authored Apr 28, 2005 by Christoph Lameter Committed by Linus Torvalds Apr 28, 2005

[PATCH] time interpolator: Fix settimeofday inaccuracy



settimeofday will set the time a little bit too early on systems using
time interpolation since it subtracts the current interpolator offset
from the time. This used to be necessary with the code in 2.6.9 and earlier
but the new code resets the time interpolator after setting the time.
Thus the time is set too early and gettimeofday will return a time slightly
before the time specified with settimeofday if invoked immeditely after
settimeofday.

This removes the obsolete subtraction of the time interpolator offset
and makes settimeofday set the time accurately. 

Signed-off-by: Christoph Lameter <clameter@sgi.com>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

parent bdceb6a0

kernel/time.c

+0 −8

Original line number	Diff line number	Diff line
		@@ -516,14 +516,6 @@ int do_settimeofday (struct timespec *tv)

		write_seqlock_irq(&xtime_lock);
		{
		/*
		* This is revolting. We need to set "xtime" correctly. However, the value
		* in this location is the value at the most recent update of wall time.
		* Discover what correction gettimeofday would have done, and then undo
		* it!
		*/
		nsec -= time_interpolator_get_offset();

		wtm_sec = wall_to_monotonic.tv_sec + (xtime.tv_sec - sec);
		wtm_nsec = wall_to_monotonic.tv_nsec + (xtime.tv_nsec - nsec);

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