[Haskell-cafe] multi-thread and lazy evaluation

[Yuras Shumovich]

Hi,

AFAIK it is (partially?) fixed in HEAD, see
http://hackage.haskell.org/trac/ghc/ticket/367

It works for me with -fno-omit-yields

Thanks,
Yuras

On Tue, 2012-12-25 at 19:35 +0100, timothyhobbs at seznam.cz wrote:
> I'm not sure that there is anything "great" about this bug.  It seems to me 
> to be a rather severe demonstration of a somewhat already known design flaw 
> in the runtime :(
> 
> Could you please comment on the actual bug rather than replying here so that
> the devs see that this behaviour has been confirmed?
> 
> Tim
> 
> 
> ---------- Původní zpráva ----------
> Od: Corentin Dupont <corentin.dupont at gmail.com>
> Datum: 25. 12. 2012
> Předmět: Re: [Haskell-cafe] multi-thread and lazy evaluation
> 
> "
> 
> Great, with me compiled with ghc -threaded the bug shows up.
> 
> However, runnning "main" in ghci doesn't show the bug (it finishes 
> correctly).
> 
> I have GHC 7.4.1.
> 
>  
> 
> Corentin
>  
> 
> 
> On Tue, Dec 25, 2012 at 3:34 PM, <timothyhobbs at seznam.cz
> (mailto:timothyhobbs at seznam.cz)> wrote:
> " 
> This seems like a bug in GHC. But it has nothing to do with MVars.  I've 
> narrowed this down and filed a bug report here:
> 
> http://hackage.haskell.org/trac/ghc/ticket/7528
> (http://hackage.haskell.org/trac/ghc/ticket/7528)
> 
> Timothy
> 
> 
> ---------- Původní zpráva ----------
> Od: Yuras Shumovich <shumovichy at gmail.com(mailto:shumovichy at gmail.com)>
> 
> 
> Datum: 24. 12. 2012
> Předmět: Re: [Haskell-cafe] multi-thread and lazy evaluation
> 
> 
> 
> 
> "On Mon, 2012-12-24 at 16:16 +0100, timothyhobbs at seznam.cz
> (mailto:timothyhobbs at seznam.cz) wrote:
> > The real question is, does this mean that GHC is stopping the world every 
> > time it puts an MVar?
> 
> No, GHC rts only locks the MVar itself.
> See here:
> http://hackage.haskell.org/trac/ghc/browser/rts/PrimOps.cmm#L1358
> (http://hackage.haskell.org/trac/ghc/browser/rts/PrimOps.cmm#L1358)
> 
> Yuras"
> 
> 
> 
> 
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> 
> "
> 
> 
> "