[Python-Dev] PEP 564: Add new time functions with nanosecond resolution

Wes Turner wes.turner at gmail.com
Tue Oct 24 06:36:11 EDT 2017

On Tuesday, October 24, 2017, Antoine Pitrou <solipsis at pitrou.net
<javascript:_e(%7B%7D,'cvml','solipsis at pitrou.net');>> wrote:

> 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.

>From https://en.wikipedia.org/wiki/Virtual_black_hole :

> In the derivation of his equations, Einstein suggested that physical
space-time is Riemannian, ie curved. A small domain of it is approximately
flat space-time.

>From https://en.wikipedia.org/wiki/Quantum_foam :

> Based on the uncertainty principles of quantum mechanics and the general
theory of relativity, there is no reason that spacetime needs to be
fundamentally smooth. Instead, in a quantum theory of gravity, spacetime
would consist of many small, ever-changing regions in which space and time
are not definite, but fluctuate in a foam-like manner.

So, in regards to time synchronization, FWIU:

- WWVB "can provide time with an accuracy of about 100 microseconds"

- GPS time can synchronize down to "tens of nanoseconds"

- Blockchains work around local timestamp issues by "enforcing" linearity

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

> Regards
> Antoine.
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