[Python-Dev] PEP 564: Add new time functions with nanosecond resolution (original) (raw)

Antoine Pitrou solipsis at pitrou.net
Tue Oct 24 05:22:15 EDT 2017

On Tue, 24 Oct 2017 09:00:45 +0200 Victor Stinner <victor.stinner at gmail.com> wrote:

By the way, you mentionned that clocks are not synchronized. That's another revelant point. Even if system clocks are synchronized on a single computer, I read that you cannot reach nanosecond resolution for a NTP synchronization even in a small LAN.

For large systems or distributed systems, a "global (synchronized) clock" is not an option. You cannot synchronize clocks correctly, so your algorithms must not rely on time, or at least not too precise resolution. I am saying that to again repeat that we are far from sub-second nanosecond resolution for system clock.

What does synchronization have to do with it? If synchronization matters, then your PEP should be rejected, because current computers using NTP can't synchronize with a better precision than 230 ns.

See https://blog.cloudflare.com/how-to-achieve-low-latency/

Regards

Antoine.

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