[Haskell-cafe] Re: Thread pool in GHC

[genneth]

I think it would go back to the pool. The finally clause means that
even if the thread dies from an exception (which, AFAIK, is how kills
are modelled), the thread count would be restored.

Gen

On 9/6/05, Dinh Tien Tuan Anh <tuananhbirm at hotmail.com> wrote:
> 
> Its probably too long to bring back this topic, but i have a small question.
> 
> If some threads may never terminate and have to be killed by killThread, are
> they going back to the pool, or we need some twist to force them.
> 
> Thanks a lot
> TuanAnh
> 
> >From: genneth <genneth at gmail.com>
> >To: haskell-cafe at haskell.org
> >Subject: [Haskell-cafe] Re: Thread pool in GHC
> >Date: Thu, 4 Aug 2005 16:47:56 +0000 (UTC)
> >
> >Dinh Tien Tuan Anh <tuananhbirm <at> hotmail.com> writes:
> >
> > >
> > >
> > >   Can thread pool be implemented in GHC ?
> > >
> > > I have a program that is currently using about 12-15 threads (launch and
> > > kill for infinite times) and when running, especially after Ctrl-C, my
> > > computer got freezed up. And if i ran it several times, the "Stack
> > > overflows" occurs.
> >
> >I made the following a while back. Maybe it's useful...
> >
> >limitedThreadsWithChannelMapM :: Integer -> (a -> IO b) -> [a] -> IO [MVar
> >b]
> >limitedThreadsWithChannelMapM lim ioaction x = do
> >     threadpoolcounter <- atomically ( newTVar 0 )
> >     mapM (throttledFork threadpoolcounter . ioaction) x
> >     where
> >         throttledFork poolcount io = do
> >             atomically ( do
> >                 prev <- readTVar poolcount
> >                 if prev >= lim then
> >                     retry
> >                     else writeTVar poolcount (prev+1) )
> >             mvar <- newEmptyMVar
> >             forkIO(
> >                 finally
> >                     (io >>= putMVar mvar)
> >                     (atomically ( readTVar poolcount >>= writeTVar
> >poolcount .
> >(subtract 1) ) ) )
> >             return mvar
> >
> > >
> > > Cheers
> > > TuanAnh
> > >
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