Forked thread running infinite loop blocks other threads from running
When I compile the following under GHC 7.2.2 with -O1 or -O2, it spins in the forked thread's infinite loop. The forked thread does not yield control to the main thread:
import Control.Concurrent
import Control.Monad
main :: IO ()
main = do
tid <- forkIO $ forever $ return ()
putStrLn $ "Forked " ++ show tid
This happens up even if I compile with -threaded -rtsopts, use +RTS -N2, and use forkOS instead of forkIO.
The problem goes away if I disable optimization. It also goes away if I stick a yield :: IO () call in the loop.
Trac metadata
Trac field | Value |
---|---|
Version | 7.2.2 |
Type | Bug |
TypeOfFailure | OtherFailure |
Priority | normal |
Resolution | Unresolved |
Component | Runtime System |
Test case | |
Differential revisions | |
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Blocking | |
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Operating system | |
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