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Re: NIO multiplexing + thread pooling

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Hi Tom,

Thank you for your insights.

On 9/24/11 9:46 PM, in article
<twic@urchin.earth.li> wrote:
> 
> If the selector thread's only job is to identify channels which are ready
> to be worked on, handing them off to worker threads to be processed, then
> it doesn't really have a lot of work of its own to do, and so it's
> unlikely to be a bottleneck.
> 
> If you're processing the channels in the selector thread (in which case
> it's not really a selector thread), then it could be a bottleneck. So, you
> can have several of them; Selector.select() is threadsafe, so with a
> little attention to locking, you can have many threads selecting and then
> working. This is called the leader/followers model.
> 
> One thing you could consider, if using a single selector thread and a pool
> of worker threads, is trying to create some affinity between channels and
> threads, so that the same thread always handles the work on a particular
> channel (and on several channels); on a multiprocessor machine, this
> should increase cache performance, but is not otherwise particularly
> valuable. This is not entirely straightforward, because of thread and
> channel starvation issues; you should read up on work-stealing if you want
> to do that.
> 
This is exactly what I was asking in the OP, this "affinity between channels
and threads" as you call it. I didn't mean a "thread-per-connection model".
I will try to find a way to implement this affinity on top of the
ThreadPoolExecutor even though it is not very clear from its API that it can
be done.

Among others, I was following this tutorial
<http://rox-xmlrpc.sourceforge.net/niotut/index.html> and there he overloads
a bit the single "Selector Thread" for reading and sending data. AFAIK there
is no sample code doing Selector.select() from separate threads.

Thank you again.
Best regards,
Giovanni

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Thread

NIO multiplexing + thread pooling Giovanni Azua <bravegag@hotmail.com> - 2011-09-24 20:32 +0200
  Re: NIO multiplexing + thread pooling Tom Anderson <twic@urchin.earth.li> - 2011-09-24 20:46 +0100
    Re: NIO multiplexing + thread pooling Giovanni Azua <bravegag@hotmail.com> - 2011-09-24 23:09 +0200
    Re: NIO multiplexing + thread pooling Robert Klemme <shortcutter@googlemail.com> - 2011-09-25 11:33 +0200
      Re: NIO multiplexing + thread pooling Tom Anderson <twic@urchin.earth.li> - 2011-09-27 20:52 +0100
        Re: NIO multiplexing + thread pooling Robert Klemme <shortcutter@googlemail.com> - 2011-09-28 08:21 +0200
          Re: NIO multiplexing + thread pooling markspace <-@.> - 2011-09-28 08:20 -0700
            Re: NIO multiplexing + thread pooling Robert Klemme <shortcutter@googlemail.com> - 2011-09-28 18:56 +0200
              Re: NIO multiplexing + thread pooling markspace <-@.> - 2011-09-28 11:07 -0700
            Re: NIO multiplexing + thread pooling Peter Duniho <NpOeStPeAdM@NnOwSlPiAnMk.com> - 2011-09-28 17:39 -0700
              Re: NIO multiplexing + thread pooling markspace <-@.> - 2011-09-29 09:25 -0700
                Re: NIO multiplexing + thread pooling Lew <lewbloch@gmail.com> - 2011-09-30 07:46 -0700
                Re: NIO multiplexing + thread pooling markspace <-@.> - 2011-09-30 08:22 -0700
                Re: NIO multiplexing + thread pooling Lew <lewbloch@gmail.com> - 2011-09-30 08:30 -0700
                Re: NIO multiplexing + thread pooling markspace <-@.> - 2011-09-30 08:49 -0700
                Re: NIO multiplexing + thread pooling Robert Klemme <shortcutter@googlemail.com> - 2011-09-30 20:57 +0200
  Re: NIO multiplexing + thread pooling "John B. Matthews" <nospam@nospam.invalid> - 2011-09-25 00:26 -0400
    Re: NIO multiplexing + thread pooling Giovanni Azua <bravegag@hotmail.com> - 2011-09-25 11:13 +0200

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