[pypy-dev] minimum system requirements, build configuration

[Dima Tisnek]

Oh, I guessed your reasons.

Lanugages like python make a lot of garbage, so 16MB will fill up
pretty fast as long as the program does something at all. What I mean
to say is that there's gotta be a more clever way where gc thresholds
depend on e.g. size of working set or rate of new allocations or
something yet smarter.

d.

On 5 April 2011 12:44, Armin Rigo <arigo at tunes.org> wrote:
> Hi Dima,
>
> On Tue, Apr 5, 2011 at 9:26 PM, Dima Tisnek <dimaqq at gmail.com> wrote:
>> What I'm trying to say, is gc should adapt to run-time behaviour of a
>> particular script, in some cases 16MB heap threshold would impact both
>> user expectation and performance significantly.
>
> It may impact user expectation and performance, but:
>
> User expectation: so far we've considered the "desktop" users, which
> do not care about 10MB versus 20MB but start to care when it's about
> 300MB versus 600MB.  It's true that other categories of users exist.
> Sorry for not being able to care for all possible use cases at once
> :-)
>
> Performance: actually this setting of ours -- not collecting before we
> have at least 16MB of data -- was done to avoid degradation of
> performance in cases where the Python script has really low memory
> usage, so the idea "it's consuming 30MB instead of 5MB so it must have
> a terrible performance" sounds pretty abstract.  But again this is
> assuming a system where 30MB is a small fraction of the total amount
> of RAM.
>
> If you want to care about the use case of, say, systems with 16MB of
> RAM in total, then feel free to tweak PyPy.  I suppose that you'd get
> the best results by tweaking one of our GCs, or writing a new one.
> (For example it probably doesn't make much sense to have a nursery at
> all.)
>
>
> I hope this helps to clarify the issue,
>
> Armin
>