ForkJoin vs other thread pools in Java?

user_3610608 0
Viewed 82

Java ForkJoin pools has been compared to the other "classic" thread pool implementation in Java many times. The question I have is slightly different though:

Can I use a single, shared ForkJoin pool for an application that have BOTH types of thread usage - long running, socket-handling, transactional threads, AND short running tasks (CompletableFuture)? Or do I have to go through the pain of maintaining 2 separate pools for each type of need? ... In other words, is there a significant (performance?) penalty, if ForkJoin is used in place where other Java thread pool implementations suffice?

multithreading java
1 Answers

According to the documentation, it depends:

(3) Unless the ForkJoinPool.ManagedBlocker API is used, or the number of possibly blocked tasks is known to be less than the pool's ForkJoinPool.getParallelism() level, the pool cannot guarantee that enough threads will be available to ensure progress or good performance.

The parallelism is coupled to the amount of available CPU cores. So given enough CPU cores and not to many blocking I/O tasks, you could use the commonPool. It does not mean you should though. For one thing, ForkJoinPool is explicitly not designed for long running (blocking) tasks. For another thing, you probably want to do something with long running (blocking) tasks during shutdown.

user_30800940
Related