[pypy-dev] PyPy STM

[Ronny Pfannschmidt]

Hi,

the following is a collection of unfinished thoughts.

after my thesis i'll be experimenting with a relaxed csp-ish model
based on python native generator based continuations as well as
the new continulet-jit-3 based greenlets.

my basic assumption is that having limited amount
of shared memory is acceptable.

the csp-ish "processes" are to be modeled
as generators with yield expressions or green-lets
and will assume a strong data locality.

all communication will be started by suspending the execution and 
"switching away" with some payload

that kind of starting/stopping seems to lend itself well to stm transactions

basically one iteration of a generator will be one transaction
and internal communication will also be separate transactions

my current hypothesis is that such a model will lend itself to easy 
parallel execution since iteration steps of different continuations will 
be mostly completely independent and can just run in parallel.

communication itself will be in transactions with higher conflict potential,
but i assume that armin will find ways
to evade the conflict issues with in-process communication channels,
so i'm not going to think about it more till
it turns out to be an actual problem in experimentation

My main focus with those experiments will be concurrent systems.


-- Ronny



On 09/30/2012 11:10 AM, Russel Winder wrote:
> Armin,
>
> Sarah and I are restarting our work on CSP, and extending to creating
> actors and a dataflow library. It would be good to make this work on
> Jython, IronPython and PyPy as well as CPython. However we want to get
> away from a reliance on multiprocessing since it is rather heavyweight
> for the sort of parallelism we are after. STM as an infrastructure layer
> in PyPy and CPython would get us away from the GIL and allow for using
> Python threads bound to kernel threads to allow a single Python process
> to allow us to create lighweight processes (no application level shared
> memory).
>
> Is the STM variant of PyPy and/or CPython in any form of usable state?
> If so then we can investigate building from source for ourselves so as
> to use it as a foundation for building the higher abstraction
> parallelism for applications programmers.
>
> Thanks.
>
>
>
>
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