[Python-Dev] Drop the new time.wallclock() function?
anacrolix at gmail.com
Thu Mar 15 11:06:44 CET 2012
On Mar 15, 2012 4:23 PM, "Paul Moore" <p.f.moore at gmail.com> wrote:
> On 15 March 2012 01:58, Matt Joiner <anacrolix at gmail.com> wrote:
> > Victor, I think that steady can always be monotonic, there are time
> > enough to ensure this on the platforms I am aware of. Strict in this
> > refers to not being adjusted forward, i.e. CLOCK_MONOTONIC vs
> > CLOCK_MONOTONIC_RAW.
> I agree - Kristján pointed out that you can ensure that backward jumps
> never occur by implementing a cache of the last value.
Without knowing more, either QPC was buggy on his platform, or he didn't
account for processor affinity (QPC derives from a per processor counter).
> > Non monotonicity of this call should be considered a bug.
> > Strict would be used for profiling where forward leaps would disqualify
> I'm baffled as to how you even identify "forward leaps". In relation
> to what? A more accurate time source? I thought that by definition
> this was the most accurate time source we have!
Monotonic clocks are not necessarily hardware based, and may be adjusted
forward by NTP.
> +1 on a simple time.steady() with guaranteed monotonicity and no flags
> to alter behaviour.
I don't mind since I'll be using it for timeouts, but clearly the strongest
possible guarantee should be made. If forward leaps are okay, then by
definition the timer is monotonic but not steady.
-------------- next part --------------
An HTML attachment was scrubbed...
More information about the Python-Dev