kernel_optimize_test/arch/powerpc
Paul Mackerras 0a45d4491d powerpc: Fix problem with time going backwards
The recent changes to keep gettimeofday in sync with xtime had the side
effect that it was occasionally possible for the time reported by
gettimeofday to go back by a microsecond.  There were two reasons:
(1) when we recalculated the offsets used by gettimeofday every 2^31
timebase ticks, we lost an accumulated fractional microsecond, and
(2) because the update is done some time after the notional start of
jiffy, if ntp is slowing the clock, it is possible to see time go backwards
when the timebase factor gets reduced.

This fixes it by (a) slowing the gettimeofday clock by about 1us in
2^31 timebase ticks (a factor of less than 1 in 3.7 million), and (b)
adjusting the timebase offsets in the rare case that the gettimeofday
result could possibly go backwards (i.e. when ntp is slowing the clock
and the timer interrupt is late).  In this case the adjustment will
reduce to zero eventually because of (a).

Signed-off-by: Paul Mackerras <paulus@samba.org>
2006-03-16 16:54:55 +11:00
..
boot powerpc/32: Generate miboot images with ARCH=powerpc 2006-01-15 13:00:08 +11:00
configs [PATCH] powerpc: Update {g5,pseries,ppc64}_defconfig 2006-02-24 11:36:35 +11:00
kernel powerpc: Fix problem with time going backwards 2006-03-16 16:54:55 +11:00
lib [PATCH] powerpc: Remove lppaca structure from the PACA 2006-01-13 21:17:39 +11:00
mm [PATCH] powerpc/iseries: Fix double phys_to_abs bug in htab_bolt_mapping 2006-02-28 16:25:55 +11:00
oprofile [PATCH] powerpc: disable OProfile for iSeries 2006-02-24 11:36:27 +11:00
platforms powerpc: Disallow lparcfg being a module 2006-03-14 11:35:37 +11:00
sysdev [PATCH] powerpc: Fix some MPIC + HT APIC buglets 2006-02-24 11:36:37 +11:00
xmon [PATCH] powerpc: xmon namespace cleanups 2006-01-12 20:39:14 +11:00
Kconfig Make Kprobes depend on modules 2006-02-26 20:24:40 -08:00
Kconfig.debug [PATCH] powerpc: Make early debugging configurable via Kconfig 2006-01-11 14:48:26 +11:00
Makefile Merge git://git.kernel.org/pub/scm/linux/kernel/git/paulus/powerpc-merge 2006-02-10 14:52:31 -08:00