Messages in this thread Patch in this message | | | Date | Wed, 12 Dec 2007 12:15:22 -0800 | Date | Wed, 12 Dec 2007 12:12:58 -0800 | From | Daniel Walker <> | Subject | [PATCH -rt] cycles_to_usecs rounding fix |
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do_div() rounds down, so we add have the divisor to round up. This effected my change to preempt_max_latency. Each time you read preempt_max_latency it gets rounded lower.
Signed-off-by: Daniel Walker <dwalker@mvista.com>
--- kernel/time/timekeeping.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-)
Index: linux-2.6.23/kernel/time/timekeeping.c =================================================================== --- linux-2.6.23.orig/kernel/time/timekeeping.c +++ linux-2.6.23/kernel/time/timekeeping.c @@ -144,7 +144,8 @@ unsigned long notrace cycles_to_usecs(cy { u64 ret = cyc2ns(clock, cycles); - do_div(ret, 1000); + ret += NSEC_PER_USEC/2; /* For rounding in do_div() */ + do_div(ret, NSEC_PER_USEC); return ret; } -- --
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