[Twisted-Python] Two main loops

glyph at divmod.com glyph at divmod.com
Thu Nov 15 13:40:43 EST 2007

On 14 Nov, 07:08 pm, drew.smathers at gmail.com wrote:
>>Actually, punting to another thread or process is still going to slow
>>down your rendering, but in a much less deterministic way.  The OS
>>scheduler is going to be interrupting the rendering rather than the
>>long-running serialization function.  Breaking down the serialization
>>work into smaller chunks will allow you to better control what's going
>Holy crap!  I just grew an extra brain cell!  It has tingly sensation 
>selson blue.

Nice to hear that we're helping to increase the transistor density of 
the universe.
>So let me offer some empirical evidence of this phenomenon which I was 
>quite understanding until reading your comment - of course, it makes
>complete sense now.  I've been working on a cheesey game in my spare 
>called Twisted Wars (yes, the Twisted), and just to amuse myself I 
>to run the reactor normally rather than threaded select and model the
>runtime loop as a cooperative iterator - the idea being that eventually 
>runtime loop could be many cooiterators, to allow for an actor-based 

I've seen Twisted Wars.  It's flattering, but I hope it's going to 
evolve from beyond its, ahem, "humble" beginnings into something more 
interesting :).  Nice to unveil the mystery of its author, though ...
>To my surprise, after changing the core runtime to a cooiterator, my 
>rate improved (albeit only about +5 - but this might be more noticeable 
>if I
>had a decent frame rate to start with).  I explained to a friend who's 
>working on the game and they refused to believe me! Ha!

Although I'm glad you've gained some insight into the exciting world of 
improving performance (or not) with parallelism, I wouldn't read too 
much into this.  threadedselectreactor is a particularly poorly-tested 
piece of code and it might have performance bugaboos of its own that 
have nothing to do with concurrency.  Also, as I said, I've tried 
Twisted Wars; one of the things I noticed about it is that the framerate 
seems to degrade slowly over time until the game becomes sluggish and 
unplayable.  It seems like you're leaking computation somewhere.  So 
you've got a lot of factors to consider when measuring your overall 

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