Jacob Erlbeck wrote:
+/* add sec,usec to tv */ +static void tv_add(struct timeval *tv, int sec, int usec) +{ + + while (usec < 0) { + usec += USEC_1S; + sec--; + } + tv->tv_sec += sec; + tv->tv_usec += usec; + while (tv->tv_usec >= USEC_1S) { + tv->tv_sec++; + tv->tv_usec -= USEC_1S; + } +}
I'm not sure whether it is a good idea to use while loops in this case since CPU usage is O(N) of the usec value.
Remember that N>1 only with very small or very large usec values, which I guess will be a corner case since it wasn't handled before?
Wouldn't it be more convenient to have a function tv_add_us(tv, usec) instead that does the div/mod stuff to a temporary timeval and then just calls timeradd()?
Is there a machine where div/mod is actually more efficient than a small number of iterations around a loop? :) Is this a hot path? Then I think it makes sense to optimize harder for performance rather than for readability. But compilers are good at that too.. //Peter