[5.5] Worker: Allow to set sleep time less than 1 seconds

[disc]

I'd like to set sleep time for worker less than 1 seconds, but I can't do this because we use sleep().
I suggest we can use usleep() and multiply passed $seconds to * 100000 for backward compatibility.
Now possible to pass 0.5 or 0.01 seconds

[themsaid]

@disk if you sleep less than 1 second why sleep at all? Can you explain the scenario where this is useful?

[disc]

@themsaid I've got a lot of queues and i'd like to decrease sleep timeout, but don't disable it.
Small sleep timeout will produce less load than disabled option.

[vlakoff]

Just to point out PHP_INT_MAX is 2147483647 on 32-bit platform, so this change would break with $seconds > 2147 (about 36 minutes).

[disc]

@vlakoff I agree. I'll rewrite this code and will use usleep in case when sleep less than 1 second

[vlakoff]

Alternatively, detect if value would be out of range, and when so, fallback to sleep().

[vlakoff]

if (PHP_INT_SIZE < 8 && $seconds >= 2147) {
    sleep($seconds);
} else {
    usleep($seconds * 1000000);
}

This way, we reduce precision only when needed, and you can sleep 1.5 seconds :)

[disc]

Fixed in #22255