Subject: bug#44674: 28.0.50; Adding current-cpu-time for performance tests

From: Mattias Engdegård <[email-masked]>
Date: Mon, 16 Nov 2020 20:15:26 +0100

16 nov. 2020 kl. 18.13 skrev Eli Zaretskii <[email-masked]>:

>> Perhaps not ideal to cons in a timing primitive where low overhead is called for.
>> What about just returning an integer and have a different way to get at TICKS-PER-SEC?
> 
> Why not just return a float in seconds instead?

Precision would vary depending on the magnitude of the time stamp (which should be irrelevant since only differences are used). Floats are also always boxed, for that matter.

> Can you make a case for process-global timing, given that we don't
> control all of the threads, and that some of them are utterly
> unrelated to timing Lisp programs?

If Lisp actions trigger work done in other threads the completion of which has to be awaited then those threads are effectively part of the same computation. (Admitted, not a very strong case.)