Messages in this thread Patch in this message | | | Date | Tue, 10 Oct 2006 10:15:19 -0700 | From | Greg KH <> | Subject | [patch 12/19] SPARC64: Fix serious bug in sched_clock() on sparc64 |
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-stable review patch. If anyone has any objections, please let us know.
------------------ From: David S. Miller <davem@davemloft.net>
[SPARC64]: Fix sched_clock() wrapping every ~17 seconds.
Unfortunately, sparc64 doesn't have an easy way to do a "64 X 64 --> 128" bit multiply like PowerPC and IA64 do. We were doing a "64 X 64 --> 64" bit multiple which causes overflow very quickly with a 30-bit quotient shift.
So use a quotientshift count of 10 instead of 30, just like x86 and ARM do.
This also fixes the wrapping of printk timestamp values every ~17 seconds.
Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
--- arch/sparc64/kernel/time.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
--- linux-2.6.17.13.orig/arch/sparc64/kernel/time.c +++ linux-2.6.17.13/arch/sparc64/kernel/time.c @@ -1105,7 +1105,7 @@ static struct time_interpolator sparc64_ }; /* The quotient formula is taken from the IA64 port. */ -#define SPARC64_NSEC_PER_CYC_SHIFT 30UL +#define SPARC64_NSEC_PER_CYC_SHIFT 10UL void __init time_init(void) { unsigned long clock = sparc64_init_timers(); -- - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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