From: Shuya MAEDA <[EMAIL PROTECTED]>
Date: Mon, 19 Jun 2006 14:36:46 +0900
> #define PSCHED_TADD2(tv, delta, tv_res) \
> ({ \
> - int __delta = (tv).tv_usec + (delta); \
> - (tv_res).tv_sec = (tv).tv_sec; \
> - if (__delta > USEC_PER_SEC) { (tv_res).tv_sec++; __delta -=
> USEC_PER_SEC; } \
> - (tv_res).tv_usec = __delta; \
> + int __delta = (delta); \
> + (tv_res) = (tv); \
> + if((delta) > USEC_PER_SEC) { \
> + (tv_res).tv_sec += (delta) / USEC_PER_SEC; \
> + __delta -= (delta) % USEC_PER_SEC; \
> + } \
> + (tv_res).tv_usec += __delta; \
> + if((tv_res).tv_usec >= USEC_PER_SEC) { \
> + (tv_res).tv_sec++; \
> + (tv_res).tv_usec -= USEC_PER_SEC; \
> + } \
> })
Divide and modulus can be extremely expensive on some systems, so
let's try to avoid using them.
It is probably sufficient to adjust the passed in delta only once if
it is >= USEC_PER_SEC, but if you feel that is an unsafe assumption
then please use a simply loop like this:
while (__delta >= USEC_PER_SEC) {
(tv_res).tv_sec++;
__delta -= USEC_PER_SEC;
}
And please provide a proper "Signed-off-by: " line in your next
patch submission.
Thank you very much.
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