How might I go about finding out how many processors are available in a concurrent GHC program? I have some code I'd like to parallelize, but I don't want to spawn a separate (even lightweight) thread for each of thousands of minor tasks. Louis Wasserman wasserman.louis@gmail.com
wasserman.louis:
How might I go about finding out how many processors are available in a concurrent GHC program? I have some code I'd like to parallelize, but I don't want to spawn a separate (even lightweight) thread for each of thousands of minor tasks.
Louis Wasserman [1]wasserman.louis@gmail.com
You set the number of OS threads with +RTS -N at runtime. This value is accessible from Haskell via: GHC.Conc: -- | the value passed to the @+RTS -N@ flag. This is the number of -- Haskell threads that can run truly simultaneously at any given -- time, and is typically set to the number of physical CPU cores on -- the machine. numCapabilities :: Int -- Don
2009/1/22 Louis Wasserman
How might I go about finding out how many processors are available in a concurrent GHC program? I have some code I'd like to parallelize, but I don't want to spawn a separate (even lightweight) thread for each of thousands of minor tasks.
Use a thread pool and feed it tasks. Control.Concurrent.Chan makes a good queue. Thomas
2009/1/22 Louis Wasserman
How might I go about finding out how many processors are available in a concurrent GHC program? I have some code I'd like to parallelize, but I don't want to spawn a separate (even lightweight) thread for each of thousands of minor tasks.
Consider using Contorl.Parallel.Strategies which allows you to spark of lightweight jobs that get run on a pool of threads. -- Sebastian Sylvan +44(0)7857-300802 UIN: 44640862
participants (4)
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Don Stewart -
Louis Wasserman -
Sebastian Sylvan -
Thomas DuBuisson