[Stackless] EuroPython 2010 Trip Report

Andrew Francis andrewfr_ice at yahoo.com
Sat Jul 24 14:07:50 CEST 2010


Hi Richard:

--- On Sat, 7/24/10, stackless-request at stackless.com <stackless-request at stackless.com> wrote:

> Message: 2
> Date: Sat, 24 Jul 2010 07:54:36 +0800
> From: Richard Tew <richard.m.tew at gmail.com>
> To: The Stackless Python Mailing List <stackless at stackless.com>
> Subject: Re: [Stackless] EuroPython 2010 Trip Report
> Message-ID:
>     <AANLkTi=E0mMDgZUaRR0=wsFVDfiHVyZWAkKeDRHPZfVw at mail.gmail.com>
> Content-Type: text/plain; charset=ISO-8859-1


> Congratulations Christian, it is well deserved.

:-)


> I know I could google this, but I imagine other people are
> wondering as well.  So maybe you could elaborate on exactly what
> Guido sees a sub-generator as?

Well Raymond Hettinger, author of PEP 342 in his generators talk,
used the term as well. Essentially nested generators. Also in the
talk, Hettinger listed Stackless as an asynchronous framework. 
However nested/sub generators sounds like it is on a wishlist and 
years away, if done. I don't see what that would give Python that Stackless doesn't give today. And Stackless Python is a moving target
too.

> Indeed.  While now Stackless may have a certain amount
> of documentation and example code, and it may have installers
> and a few other accoutrements that make it more approachable and
> useful.. it is still an alternate installation of Python.  Either we
> need to start talking some smack about greenlet based solutions, or we
> need to address this.  Which shall it be? ;-)

Well a lot the greenlet based smack is already there with stackless.py
using greenlets over Standard Python. I don't want to sound mystical but Stackless Python is more a family of Python based concurrency solutions than a single binary. When I talked to Denis Bilenko, he wondered how greenlets were to be used with Stackless. This boiled down to what was 
the use of a scheduler. I think one can live without a scheduler (or an implicit one run directly by the reactor) in a totally reactive Internet application like a web server. However what happens when one starts to have applications that have a hierarchical structure (i.e, a network of event processing agents) and there are entire levels of coroutines that are not directly tied to low level I/0? Now I think things like fairness come into play and one really wants a scheduler.

However I think the real problem is coming up with a good networking
solution. 

> Sounds like a great experience

It was. I think Antonio has forgiven me for using vi.

> Personally my only concern is that the addition of this to 
>the main Stackless module in PyPy moves it away from however 
>much of a one-to-one representation of the functionality in 
>the "real Stackless".

Well the current situation is a wee more interesting. There
is also a Stackless Python C source code version of the select
thanks to my friend Kevin. So on the one hand, my changes are 
going in lock step. But now we face having another Stackless
Python branch. I am not sure how Kristjan handles the branch with
tasklet priorities. That said, I am debugging. I want to put a 
new patch out there and many many more tests out there. This is
where I finally start diving into C and the Stackless Python 
source in earnest.

> Is this a bad thing? 

No.

> Is PyPy still mooted as the future of Stackless? Or is that 
>Stackless lite?  

I think both are a part of the future. And PyPy creates choices.
Prototying features in Stackless is one of them. Allowing
organizations to create customized Pythons with relatively good 
performance is another. 

>Speaking of which, maybe some of us should step forward and offer 
>to help Christian with that, in order to take Stackless to the next level >and show those greenlet hooligan what's what.

Sounds good. Where do I sign up? 
 
> Anyway, it sounds like you had a great time.  Reading
> about your experiences makes me wish I was there, but CCP don't pay
> for me to travel to conferences anymore since I am no longer an
> employee.

Well if I were an artist, the Canada Council would have subsidized my trip. Traveling to England in July is brutally expensive but what the hey, I had a blast. And what company would allow me to implement select in a pub on a Sunday while watching the World Cup. 

Stackless is such a cool gig.....

Cheers,
Andrew 








      




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