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[PATCH] fix and optimize clock source update

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This fixes the clock source updates in update_wall_time() to correctly
track the time coming in via current_tick_length().  Optimize the fast
paths to be as short as possible to keep the overhead low.

Signed-off-by: Roman Zippel <zippel@linux-m68k.org>
Acked-by: John Stultz <johnstul@us.ibm.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
This commit is contained in:
Roman Zippel
2006-06-26 00:25:18 -07:00
committed by Linus Torvalds
parent 6415ce9a92
commit 19923c190e
4 changed files with 124 additions and 150 deletions
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4
arch/powerpc/kernel/time.c
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@@ -102,7 +102,7 @@ EXPORT_SYMBOL(tb_ticks_per_sec); /* for cputime_t conversions */
u64 tb_to_xs;
unsigned tb_to_us;
#define TICKLEN_SCALE (SHIFT_SCALE - 10)
#define TICKLEN_SCALE TICK_LENGTH_SHIFT
u64 last_tick_len; /* units are ns / 2^TICKLEN_SCALE */
u64 ticklen_to_xs; /* 0.64 fraction */
@@ -534,7 +534,7 @@ static __inline__ void timer_recalc_offset(u64 cur_tb)
if (__USE_RTC())
return;
tlen = current_tick_length(SHIFT_SCALE - 10);
tlen = current_tick_length();
offset = cur_tb - do_gtod.varp->tb_orig_stamp;
if (tlen == last_tick_len && offset < 0x80000000u)
return;