is it possibly something related to how the gc interacts with that many threads in that context?
On Sat, Mar 13, 2010 at 11:36 AM, Michael Lesniak <mlesn...@uni-kassel.de>wrote: > Hello, > > In one of my example programs I have a strange behaviour: it is a very > simple taskpool using STM; in pseudocode it's > > 1. generate data structures > 2. initialize data structures > 3. fork threads > 4. wait (using STM) until the pool is empty and all threads are finished > 5. print a final message > > In very few cases, which depend on the number of threads spawned, the > program hangs *after* the final message of step 5 has been printed. > "Few cases" means, for example, 50.000 good, terminating runs before > it hangs. If you increment the number of spawned threads (to a few > hundred or thousands), it hangs much faster. Since forked threads > terminate after the main thread terminates (which it should after > printing the message), this behaviour is quite unexpected. > > Since I've experienced strange behaviour in the past which was the > fault of my system configuration[1], I am a bit cautious before > reporting a bug on GHC's bugtracker, especially since its reproduction > is so difficult and random. > > So my question is how much circumspection is expected/needed before > one should enter a bug in the bug tracker? I've tested the attached > code on three different systems (with different linux systems, but > always GHC 6.12.1 (since it's a bit costly to install the older > versions)) and observed the mentioned behaviour. Is this enough to > justify a bug report? Or, on the other hand, could someone spot the > error in the attached code. Given my history with strange parallel > behaviour, I am much more sure that it's the fault of my code, but I > can't spot the error and the described behaviour (halting *after* the > final message) is really strange. > > > Cheers, > Michael > > [1] http://www.haskell.org/pipermail/haskell-cafe/2010-March/073938.html > > _______________________________________________ > Haskell-Cafe mailing list > Haskell-Cafe@haskell.org > http://www.haskell.org/mailman/listinfo/haskell-cafe > >
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