#4391: forkIO threads do not properly save/restore the floating point
environment
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Reporter: draconx | Owner:
Type: bug | Status: new
Priority: normal | Milestone: 7.2.1
Component: Runtime System | Version: 6.12.3
Keywords: | Testcase:
Blockedby: | Difficulty:
Os: Unknown/Multiple | Blocking:
Architecture: x86_64 (amd64) | Failure: None/Unknown
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Changes (by simonmar):
* component: Compiler => Runtime System
Comment:
I doubt we'll fix this. The floating-point environment is 9 words of
stuff (according to my rough count), whereas a Haskell thread is 17 words.
Typically the amount of stuff saved and restored over a context switch is
only a handful of words, which is why Haskell threads are so cheap. If we
had to save the floating point unit state as well, that would
significantly impact thread performance.
Is it terrible to require the use of OS threads for this? Or is there
some way we can avoid saving and restoring the full FP state?
--
Ticket URL: <http://hackage.haskell.org/trac/ghc/ticket/4391#comment:2>
GHC <http://www.haskell.org/ghc/>
The Glasgow Haskell Compiler
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