On Tue, 9 Jun 2020 15:07:19 -0400
Vivien Didelot <vivien.dide...@gmail.com> wrote:
>
> +#define NSEC_PER_SEC 1000000000L
> +
> static inline void
> calculate_timestamp(struct timeval *ts) {
> uint64_t cycles;
> @@ -294,8 +296,14 @@ calculate_timestamp(struct timeval *ts) {
>
> cycles = rte_get_timer_cycles() - start_cycles;
> cur_time.tv_sec = cycles / hz;
> - cur_time.tv_usec = (cycles % hz) * 1e6 / hz;
> - timeradd(&start_time, &cur_time, ts);
> + cur_time.tv_usec = (cycles % hz) * NSEC_PER_SEC / hz;
> +
> + ts->tv_sec = start_time.tv_sec + cur_time.tv_sec;
> + ts->tv_usec = start_time.tv_usec + cur_time.tv_usec;
> + if (ts->tv_usec >= NSEC_PER_SEC) {
> + ts->tv_usec -= NSEC_PER_SEC;
> + ts->tv_sec += 1;
> + }
> }
>
You may want to pre-compute the reciprocal here to save the expensive
cost of divide in the fast path. See rte_reciprocal.
