[Python-Dev] Design Philosophy: Performance vs Robustness/Maintainability

[Ethan Furman]

On 07/18/2017 09:16 AM, Antoine Pitrou wrote:
> On Tue, 18 Jul 2017 09:08:08 -0700
> Ethan Furman <ethan at stoneleaf.us> wrote:
>>
>> Nick Coughlan:
>> -------------
>
> It is "Nick Coghlan" not "Coughlan".

Argh.  Sorry, Nick, and thank you, Antoine!

>>> As another example of this: while trading the global import lock for
>>> per-module locks eliminated most of the old import deadlocks, it turns
>>> out that it *also* left us with some fairly messy race conditions and
>>> more fragile code (I still count that particular case as a win
>>> overall, but it definitely raises the barrier to entry for maintaining
>>> that code).
>>>
>>> Unfortunately, these are frequently cases where the benefits are
>>> immediately visible (e.g. faster benchmark results, removing
>>> longstanding limitations on user code), but the downsides can
>>> literally take years to make themselves felt (e.g. higher defect rates
>>> in the interpreter, subtle bugs in previously correct user code that
>>> are eventually traced back to interpreter changes).
>
> I'll reply here again: the original motivation for the per-module
> import lock was not performance but correctness.

I meant that as an example of the dangers of increased code complexity.

--
~Ethan~