Re: Restart pg_usleep when interrupted

On Fri, Jul 12, 2024 at 12:14:56PM -0500, Sami Imseih wrote:
> 1/ TimestampDifference has a dependency on gettimeofday,
> while my proposal utilizes clock_gettime. There are old discussions
> that did not reach a conclusion comparing both mechanisms.
> My main conclusion from these hacker discussions [1], [2] and other
> online discussions on the topic is clock_gettime should replace
> getimeofday when possible. Precision is the main reason.
>
> 2/ It no longer uses the remain time. I think the remain time
> is still required here. I did a unrealistic stress test which shows
> the original proposal can handle frequent interruptions much better.

My comment was mostly about coding style and not about gettimeofday()
versus clock_gettime(). What does your testing show when you don't have
the extra check, i.e.,

struct timespec delay;
struct timespec remain;

delay.tv_sec = microsec / 1000000L;
delay.tv_nsec = (microsec % 1000000L) * 1000;

while (nanosleep(&delay, &remain) == -1 && errno == EINTR)
delay = remain;

--
nathan