7165762: (aio) Default thread pool should be configured so that threads terminated after a timeout period

[Chris Hegarty]

Given your detailed description, it makes reviewing the trivial patch 
easy. Looks fine to me.

-Chris.

On 30/11/2012 13:40, Alan Bateman wrote:
>
> This is something that we discussed here back in April [1].
>
> To re-cap, the thread pool for the default channel group is a cached
> thread pool where the threads don't terminate after an idle time. The
> reason for that is because of support for Windows editions that didn't
> support thread agnostic I/O (so we have to keep the threads alive,
> otherwise any I/O operations that they initiated would abort when the
> thread terminated). It was an oversight that this went into shared code
> to be used for all platforms (including newer version of Windows where
> this is not a concern).
>
> As the older editions of Windows are dying out (Windows Server 2003 is
> now in extended support, long superseded by Windows Server 2008 and
> newer) then it's probably not worth refactoring this now and that the
> simplest thing is to just change it to use Executors.newCachedThreadPool
> so that all platforms get a thread pool where the threads to terminate
> after an idle time. The patch with the trivial change to do this is
> attached.
>
> I've decided not to include a test case, mostly because it would take a
> long time (>1min) and also would be a bit fragile when with residual
> thread left behind by tests that were run previously in the same VM --
> this is an issue that we've had in other areas where the thread count
> changes for reasons attributable to other tests.
>
> Thanks,
> Alan.
>
> diff --git a/src/share/classes/sun/nio/ch/ThreadPool.java
> b/src/share/classes/sun/nio/ch/ThreadPool.java
> --- a/src/share/classes/sun/nio/ch/ThreadPool.java
> +++ b/src/share/classes/sun/nio/ch/ThreadPool.java
> @@ -102,11 +102,7 @@ public class ThreadPool {
> if (threadFactory == null)
> threadFactory = defaultThreadFactory;
> // create thread pool
> - ExecutorService executor =
> - new ThreadPoolExecutor(0, Integer.MAX_VALUE,
> - Long.MAX_VALUE, TimeUnit.MILLISECONDS,
> - new SynchronousQueue<Runnable>(),
> - threadFactory);
> + ExecutorService executor = Executors.newCachedThreadPool(threadFactory);
> return new ThreadPool(executor, false, initialSize);
> }
>
>
> [1] http://mail.openjdk.java.net/pipermail/nio-dev/2012-April/001629.html
>
>
>