Jake Foell wrote:
using ghc v6.8.2 Problem: I am creating a program that forks two other lightweight threads. One of the forked threads seems to be stuck or dead after running successfully for a non-trivial amount of time. I am receiving no error messages. Questions: What is the best way to diagnose this problem? (perhaps a ghc upgrade to a version that includes processStatus?) Does the runtime system ensure that no thread will starve for processor time?
My initial diagnosis: by looking at log files that this program produces, it seems that the thread in question is failing while receiving a response from a server. Here is a simplified exerpt: h <- connectTo server port appendFile file "Connection Established\n" hPutStr h httpRequestString hFlush h reply <- hGetContents h appendFile file reply If I look at the tail of file that is created, I see something similar to this: ... Connection Established here is the response... Connection Established Answers to my questions and/or any advice would be appreciated. thanks
You might be able to find your problem by compiling the program with -debug and running it with +RTS -Ds. This produces debugging output from the scheduler - it's intended mainly for debugging the RTS and has a lot of info that won't make much sense to you, but it might help you find the problem. If you're curious about what the RTS is doing, there are a host of other -D<something> debugging options available when you compile with -debug, use +RTS -? to list them. Cheers, Simon