[Python-Dev] Disabling cyclic GC in timeit module

[John Arbash Meinel]

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>> If you are only measuring json encoding of a few select pieces of
>> data then it's a microbenchmark. If you are measuring the whole
>> application (or a significant part of it) then I'm not sure
>> timeit is the right tool for that.
>> 
>> Regards
>> 
>> Antoine.
>> 
> 
> When you're measuring how much time it takes to encode json, this
> is a microbenchmark and yet the time that timeit gives you is
> misleading, because it'll take different amount of time in your
> application. I guess my proposition would be to not disable gc by
> default and disable it when requested, but well, I guess I'll give
> up given the strong push against it.
> 
> Cheers, fijal

True, but it is also heavily dependent on how much other data your
application has in memory at the time. If your application has 1M
objects in memory and then goes to encode/decode a JSON string when
the gc kicks in, it will take a lot longer because of all the stuff
that isn't JSON related.

I don't think it can be suggested that timeit should grow a flag for
"put garbage into memory, and then run this microbenchmark with gc
enabled.".

If you really want to know how fast something is in your application,
you sort of have to do the timing in your application, at scale and at
load.

John
=:->

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