[Haskell-cafe] Threading and FFI

Yves Parès limestrael at gmail.com
Wed Feb 17 05:13:03 EST 2010

I've also discovered something interesting: when I link with the 'threaded'
runtime, but let the program use only one core (with '+RTS -N1'), the
problem disappears. How comes?
The whole thing remains a mystery, because I think what I'm trying to do is
quite common...

Yves Parès wrote:
> There is a minimal code which produces this issue: 
>  http://old.nabble.com/file/p27613138/func.c func.c 
>  http://old.nabble.com/file/p27613138/main.hs main.hs 
> Yves Parès wrote:
>> Well I tried both 'unsafe' and 'safe', and actually I saw no
>> difference...
>> Even with 'safe', I see a huge difference between calling a C function
>> which sleeps and another which doesn't. When there is a sleep, the other
>> thread is really slower (it just prints numbers, and I look at which pace
>> they're displayed).

Yves Parès

Live long and prosper
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