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Re: Recommendations for Lightweight Threading?

From Kevin McMurtrie <mcmurtrie@pixelmemory.us>
Newsgroups comp.lang.java.programmer
Subject Re: Recommendations for Lightweight Threading?
References <YvmdncQlVsKmJUbSnZ2dnUVZ_t4AAAAA@giganews.com> <4fdc1941$0$86808$742ec2ed@news.sonic.net> <a43d3iF1ajU1@mid.individual.net>
Date 2012-06-18 19:37 -0700
Message-ID <4fdfe5cd$0$34406$742ec2ed@news.sonic.net> (permalink)
Organization Sonic.Net

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In article <a43d3iF1ajU1@mid.individual.net>,
 Robert Klemme <shortcutter@googlemail.com> wrote:

> On 16.06.2012 07:27, Kevin McMurtrie wrote:
> 
> > It's possible to roll your own concurrency classes using compare-and-set
> > or safe races.  Custom code with reduced functionality can beat the
> > general JVM classes by a lot.
> 
> That sounds interesting: please share concrete examples where you were 
> able to beat std lib "by a lot".

Many of the utility classes in the concurrency package use locking 
because it's required for implementing general List, Map, and the 
blocking APIs.  If you needed only a small subset of features, you could 
eliminate the locks.  Eliminating the locks would reduce overhead and, 
in many cases, improve the JIT compiler optimizations.

The classic example is data that has an incredibly high read to write 
ratio.  That makes it possible to use copy-on-write rather than locking.

You can also eliminate locks for blocking methods when there is one 
thread that may block.  The blocking thread calls LockSupport.park() and 
the unblocking thread calls LockSupport.unpark().  This comes in handy 
for one worker thread performing many very small tasks.  The Java 
classes don't have this drastic limitation of a single thread so they 
need locking.  (This can work for multiple threads but the complexity 
and overhead may get out of control.)

> 
> > Minimizing thread interaction in high-performance code helps even more.
> > Writing to shared memory results in a hardware stall to sync CPU caches.
> > The bigger the system, the worse those cache syncs are.
> 
> Well, that's one of the basic principles Doug Lea calls "thread 
> confinement".  Not sharing is always more efficient than sharing when it 
> comes to multiple threads.
> 
> Kind regards
> 
> 	robert
-- 
I will not see posts from Google because I must filter them as spam

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Recommendations for Lightweight Threading? "Aaron W. Hsu" <arcfide@sacrideo.us> - 2012-06-15 17:33 -0500
  Re: Recommendations for Lightweight Threading? markspace <-@.> - 2012-06-15 15:55 -0700
    Re: Recommendations for Lightweight Threading? "Aaron W. Hsu" <arcfide@sacrideo.us> - 2012-06-15 18:12 -0500
      Re: Recommendations for Lightweight Threading? markspace <-@.> - 2012-06-15 16:31 -0700
        Re: Recommendations for Lightweight Threading? "Aaron W. Hsu" <arcfide@sacrideo.us> - 2012-06-15 20:00 -0500
        Re: Recommendations for Lightweight Threading? Robert Klemme <shortcutter@googlemail.com> - 2012-06-16 14:39 +0200
          Re: Recommendations for Lightweight Threading? Daniel Pitts <newsgroup.nospam@virtualinfinity.net> - 2012-06-16 12:13 -0700
      Re: Recommendations for Lightweight Threading? Roedy Green <see_website@mindprod.com.invalid> - 2012-06-16 00:57 -0700
  Re: Recommendations for Lightweight Threading? Lew <lewbloch@gmail.com> - 2012-06-15 15:57 -0700
    Re: Recommendations for Lightweight Threading? "Aaron W. Hsu" <arcfide@sacrideo.us> - 2012-06-15 18:12 -0500
  Re: Recommendations for Lightweight Threading? Eric Sosman <esosman@ieee-dot-org.invalid> - 2012-06-15 20:19 -0400
    Re: Recommendations for Lightweight Threading? "Aaron W. Hsu" <arcfide@sacrideo.us> - 2012-06-15 19:59 -0500
      Re: Recommendations for Lightweight Threading? Eric Sosman <esosman@ieee-dot-org.invalid> - 2012-06-15 21:37 -0400
        Controlling the Garbage Collector "Aaron W. Hsu" <arcfide@sacrideo.us> - 2012-06-16 11:51 -0500
          Re: Controlling the Garbage Collector Eric Sosman <esosman@ieee-dot-org.invalid> - 2012-06-16 14:24 -0400
            Re: Controlling the Garbage Collector markspace <-@.> - 2012-06-16 12:24 -0700
              Re: Controlling the Garbage Collector Daniel Pitts <newsgroup.nospam@virtualinfinity.net> - 2012-06-16 13:14 -0700
                Re: Controlling the Garbage Collector Eric Sosman <esosman@ieee-dot-org.invalid> - 2012-06-16 16:35 -0400
                Re: Controlling the Garbage Collector "Aaron W. Hsu" <arcfide@sacrideo.us> - 2012-06-16 19:43 -0500
                Re: Controlling the Garbage Collector Wanja Gayk <brixomatic@yahoo.com> - 2012-06-23 13:36 +0200
                Re: Controlling the Garbage Collector Robert Klemme <shortcutter@googlemail.com> - 2012-06-23 15:39 +0200
                Re: Controlling the Garbage Collector markspace <-@.> - 2012-06-16 14:34 -0700
          Re: Controlling the Garbage Collector Robert Klemme <shortcutter@googlemail.com> - 2012-06-18 04:32 -0700
            Re: Controlling the Garbage Collector Roedy Green <see_website@mindprod.com.invalid> - 2012-06-24 14:31 -0700
          Re: Controlling the Garbage Collector Arne Vajhøj <arne@vajhoej.dk> - 2012-06-20 21:19 -0400
            Re: Controlling the Garbage Collector "Aaron W. Hsu" <arcfide@sacrideo.us> - 2012-06-21 13:24 -0500
              Re: Controlling the Garbage Collector Lew <lewbloch@gmail.com> - 2012-06-21 11:37 -0700
                Re: Controlling the Garbage Collector Fred Greer <fggreer@nospam.invalid> - 2012-06-21 21:20 +0000
              Re: Controlling the Garbage Collector Eric Sosman <esosman@ieee-dot-org.invalid> - 2012-06-21 15:24 -0400
              Re: Controlling the Garbage Collector Robert Klemme <shortcutter@googlemail.com> - 2012-06-21 23:46 +0200
                Re: Controlling the Garbage Collector Jukka Lahtinen <jtfjdehf@hotmail.com.invalid> - 2012-06-25 15:28 +0300
                Re: Controlling the Garbage Collector Eric Sosman <esosman@ieee-dot-org.invalid> - 2012-06-25 09:05 -0400
                Re: Controlling the Garbage Collector Andreas Leitgeb <avl@gamma.logic.tuwien.ac.at> - 2012-06-25 17:01 +0000
                Re: Controlling the Garbage Collector Eric Sosman <esosman@ieee-dot-org.invalid> - 2012-06-25 13:45 -0400
                Re: Controlling the Garbage Collector Eric Sosman <esosman@ieee-dot-org.invalid> - 2012-06-25 13:49 -0400
                Re: Controlling the Garbage Collector Robert Klemme <shortcutter@googlemail.com> - 2012-06-25 20:41 +0200
                Re: Controlling the Garbage Collector Andreas Leitgeb <avl@gamma.logic.tuwien.ac.at> - 2012-06-26 12:25 +0000
                Re: Controlling the Garbage Collector Robert Klemme <shortcutter@googlemail.com> - 2012-06-26 06:46 -0700
                Re: Controlling the Garbage Collector Andreas Leitgeb <avl@gamma.logic.tuwien.ac.at> - 2012-06-26 16:26 +0000
                Re: Controlling the Garbage Collector Eric Sosman <esosman@ieee-dot-org.invalid> - 2012-06-26 13:07 -0400
                Re: Controlling the Garbage Collector Robert Klemme <shortcutter@googlemail.com> - 2012-06-26 22:28 +0200
                Re: Controlling the Garbage Collector Andreas Leitgeb <avl@gamma.logic.tuwien.ac.at> - 2012-06-26 23:49 +0000
                Re: Controlling the Garbage Collector Lew <lewbloch@gmail.com> - 2012-06-26 18:20 -0700
                Re: Controlling the Garbage Collector Highway to Hell <HtH49439112@gmail.com> - 2012-06-26 21:52 -0400
                Re: Controlling the Garbage Collector Gene Wirchenko <genew@ocis.net> - 2012-06-26 20:01 -0700
                Re: Controlling the Garbage Collector Highway to Hell <HtH49439112@gmail.com> - 2012-06-26 23:23 -0400
                Re: Controlling the Garbage Collector Gene Wirchenko <genew@ocis.net> - 2012-06-27 09:05 -0700
                Re: Controlling the Garbage Collector Martin Gregorie <martin@address-in-sig.invalid> - 2012-06-27 20:15 +0000
                Re: Controlling the Garbage Collector Gene Wirchenko <genew@ocis.net> - 2012-06-27 13:52 -0700
                Re: Controlling the Garbage Collector Lew <lewbloch@gmail.com> - 2012-06-27 13:41 -0700
                Re: Controlling the Garbage Collector Gene Wirchenko <genew@ocis.net> - 2012-06-27 19:02 -0700
                Re: Controlling the Garbage Collector Martin Gregorie <martin@address-in-sig.invalid> - 2012-06-28 21:45 +0000
                Re: [OT] Driver's license restrictions (Was: Controlling the Garbage Collector) Lew <lewbloch@gmail.com> - 2012-06-28 15:16 -0700
                Re: [OT] Driver's license restrictions (Was: Controlling the Garbage Collector) Martin Gregorie <martin@address-in-sig.invalid> - 2012-06-29 02:10 +0000
                Re: [OT] Driver's license restrictions (Was: Controlling the Garbage Collector) Gene Wirchenko <genew@ocis.net> - 2012-06-28 19:57 -0700
                Re: [OT] Driver's license restrictions glen herrmannsfeldt <gah@ugcs.caltech.edu> - 2012-06-29 04:06 +0000
                Re: [OT] Driver's license restrictions Tim Slattery <Slattery_T@bls.gov> - 2012-06-29 08:35 -0400
                Re: [OT] Driver's license restrictions (Was: Controlling the Garbage Collector) Tim Slattery <Slattery_T@bls.gov> - 2012-06-29 08:33 -0400
                Re: Controlling the Garbage Collector Tim Slattery <Slattery_T@bls.gov> - 2012-06-29 08:30 -0400
                Re: Controlling the Garbage Collector Martin Gregorie <martin@address-in-sig.invalid> - 2012-06-29 23:04 +0000
                Re: Controlling the Garbage Collector Highway to Hell <HtH49439112@gmail.com> - 2012-06-27 16:53 -0400
                Re: Controlling the Garbage Collector Leif Roar Moldskred <leifm@dimnakorr.com> - 2012-06-27 11:32 -0500
                Re: Controlling the Garbage Collector Highway to Hell <HtH49439112@gmail.com> - 2012-06-27 16:54 -0400
                Re: Controlling the Garbage Collector Lew <lewbloch@gmail.com> - 2012-06-27 11:45 -0700
                Re: Controlling the Garbage Collector Highway to Hell <HtH49439112@gmail.com> - 2012-06-27 16:55 -0400
                Re: Controlling the Garbage Collector glen herrmannsfeldt <gah@ugcs.caltech.edu> - 2012-06-27 02:06 +0000
                Re: Controlling the Garbage Collector Andreas Leitgeb <avl@gamma.logic.tuwien.ac.at> - 2012-06-27 16:34 +0000
                Re: Controlling the Garbage Collector Leif Roar Moldskred <leifm@dimnakorr.com> - 2012-06-27 11:45 -0500
                Re: Controlling the Garbage Collector Wanja Gayk <brixomatic@yahoo.com> - 2012-07-02 11:21 +0200
                Re: Controlling the Garbage Collector Lew <lewbloch@gmail.com> - 2012-06-26 13:52 -0700
                Re: Controlling the Garbage Collector Andreas Leitgeb <avl@gamma.logic.tuwien.ac.at> - 2012-06-26 23:40 +0000
                Re: Controlling the Garbage Collector Lew <lewbloch@gmail.com> - 2012-06-26 16:48 -0700
              Re: Controlling the Garbage Collector markspace <-@.> - 2012-06-21 15:15 -0700
                Re: Controlling the Garbage Collector Lew <lewbloch@gmail.com> - 2012-06-21 15:33 -0700
                Re: Controlling the Garbage Collector "Aaron W. Hsu" <arcfide@sacrideo.us> - 2012-06-21 21:24 -0500
              Re: Controlling the Garbage Collector markspace <-@.> - 2012-06-21 15:23 -0700
        Re: Recommendations for Lightweight Threading? Wanja Gayk <brixomatic@yahoo.com> - 2012-06-17 15:49 +0200
    Re: Recommendations for Lightweight Threading? Roedy Green <see_website@mindprod.com.invalid> - 2012-06-16 01:00 -0700
      Re: Recommendations for Lightweight Threading? Roedy Green <see_website@mindprod.com.invalid> - 2012-06-16 01:04 -0700
  Re: Recommendations for Lightweight Threading? Wanja Gayk <brixomatic@yahoo.com> - 2012-06-16 04:03 +0200
  Re: Recommendations for Lightweight Threading? Kevin McMurtrie <mcmurtrie@pixelmemory.us> - 2012-06-15 22:27 -0700
    Re: Recommendations for Lightweight Threading? Robert Klemme <shortcutter@googlemail.com> - 2012-06-16 14:39 +0200
      Re: Recommendations for Lightweight Threading? Kevin McMurtrie <mcmurtrie@pixelmemory.us> - 2012-06-18 19:37 -0700
        Re: Recommendations for Lightweight Threading? Robert Klemme <shortcutter@googlemail.com> - 2012-06-19 07:46 -0700

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