Re: [Haskell-cafe] Real-time garbage collection for Haskell

On Monday 01 March 2010 01:04:37 am Luke Palmer wrote:

On Sun, Feb 28, 2010 at 2:06 AM, Pavel Perikov wrote:

...

Did you really seen 100ms pauses?! I never did extensive research on this but my numbers are rather in microseconds range (below 1ms). What causes such a long garbage collection? Lots of allocated and long-living objects?

This is all hypothetical right now. I heard some horror stories in which people had to switch to the main game loop in C++ and only do the AI logic in Haskell because of pauses. I would rather not do that, especially because this project is *about* proving Haskell as a viable game development platform. So I am trying to be prepared if I do see something like that, so that it doesn't put the show on hold for a few months.

Presumably large, long-living objects would cause the generation 0 collections to take a long time. I am not sure if we will have any said objects, but we can't rule it out...

Thanks for the positive reassurances, at least. I'd like to hear from people with the opposite experience, if there are any.

Yes there are. I am working on a game with Haskell using OpenGL rendering. I've done some frame time measurements lately and encountered single frames needing more than 100ms to be rendered. I am currently trying to gather information on what is going on in these 100ms and why. From what i understand, the GC is running very often and just some (very few) of its runs are very slow. BTW: switching to parallel GC (either with -N1 or -N2 (on a dual core machine)) made the behavior MUCH worse, for some reason. Sönke

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