Hello Simon, Friday, March 31, 2006, 4:57:19 PM, you wrote:
threadSetPriority :: ThreadID -> Int -> IO ()
it was requested by Joel Reymont, and he even give us information how that is implemented in Erlang, together with hint to assign higher priorities to consuming threads.
Yes, but the Erlang implementation doesn't do anything about priority inversion. Also, I don't think Joel really wanted priorities, his problem could have been solved by using bounded channels.
to be exact, his problem (1000 producers and one consumer) can be solved ONLY by using some bounded queue. but for typical usage when there are one or several producers and one consumer, priorities allow to solve problem: 1) in easier and more intuitive way, that is well known from other environments (Unix, for example) 2) without introducing new data structures - bounded channels, bounded priority queues and so on, so on (although it should be easy to construct them) priorities are also useful for solving other problems, where bounded queues can't help us. as i said, my own program contains one thread that reads thousands of files from disk and pushes their data into the queue. then other threads process these data. as you can see, first thread is I/O-bound while other is CPU-bound. of course, i want to give higher priority to the first thread so that it reads next portion of data as soon as previous read operation is complete (and there is free buffer). how can i accomplish it with current ghc implementation? -- Best regards, Bulat mailto:Bulat.Ziganshin@gmail.com