On Wed, 8 Jan 2020 08:56:11 +0100 Zelphir Kaltstahl <zelphirkaltst...@posteo.de> wrote: [snip] > So my questions are: > > - Is there a default / recommended way to limit parallelism for > recursive calls to parallel forms? > > - Is there a better way than a global counter with locking, to limit the > number of futures created during recursive calls? I would dislike very > much to have to do something like global state + mutex. > > - What do you recommend in general to solve this?
I think you have it wrong, and that futures use a global queue and a global set of worker threads. I don't see how futures could work without at least a global set of worker threads. Have a look at the futures source code. If you want more control over the thread pool than guile's futures provide, you could consider something like this: https://github.com/ChrisVine/guile-a-sync2/blob/master/a-sync/thread-pool.scm But then you would have to make your own futures if you want a graph of futures rather than a graph of coroutines (which is what you would get if you use the associated event loop). The main thing is to get the parallel algorithm right, which can be tricky.
