Hello Neil, Tuesday, April 7, 2009, 7:33:25 PM, you wrote:
> parallel_ (x1:xs) = do > sem <- newQSem $ 1 - length xs > forM_ xs $ \x -> > writeChan queue (x >> signalQSem sem, False) > x1 > addWorker > waitQSem sem > writeChan queue (signalQSem sem, True) > waitQSem sem > Where the second flag being True = kill, as you suggested. I think > I've got the semaphore logic right - anyone want to see if I missed > something? Neil, executing x1 directly in parallel_ is incorrect idea. you should have N worker threads, not N-1 threads plus one job executed in main thread. imagine that you have 1000 jobs and N=4. that you will got here is 3 threads each executed 333 jobs and 1 job executed by main thread so you still need to detach one more worker job and finish it just before we are ready to finish waiting for QSem and continue in main thread which is sole reason why we need killItself flag. in this code snipped this flag is completely useless, btw -- Best regards, Bulat mailto:[email protected] _______________________________________________ Haskell-Cafe mailing list [email protected] http://www.haskell.org/mailman/listinfo/haskell-cafe
