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

Ben Hoyt benhoyt at gmail.com
Mon Oct 16 12:14:00 EDT 2017


Got it -- fair enough.

We deploy so often where I work (a couple of times a week at least) that
104 days seems like an eternity. But I can see where for a very stable file
server or something you might well run it that long without deploying. Then
again, why are you doing performance tuning on a "very stable server"?

-Ben

On Mon, Oct 16, 2017 at 11:58 AM, Guido van Rossum <guido at python.org> wrote:

> On Mon, Oct 16, 2017 at 8:37 AM, Ben Hoyt <benhoyt at gmail.com> wrote:
>
>> I've read the examples you wrote here, but I'm struggling to see what the
>> real-life use cases are for this. When would you care about *both* very
>> long-running servers (104 days+) and nanosecond precision? I'm not saying
>> it could never happen, but would want to see real "experience reports" of
>> when this is needed.
>>
>
> A long-running server might still want to log precise *durations* of
> various events. (Durations of events are the bread and butter of server
> performance tuning.) And for this it might want to use the most precise
> clock available, which is perf_counter(). But if perf_counter()'s epoch is
> the start of the process, after 104 days it can no longer report ns
> precision due to float rounding (even though the internal counter does not
> lose ns).
>
> --
> --Guido van Rossum (python.org/~guido)
>
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