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Groups > comp.lang.forth > #41712

Re: GA144 use cases

From Bernd Paysan <bernd.paysan@gmx.de>
Newsgroups comp.lang.forth
Subject Re: GA144 use cases
Date 2015-09-04 01:28 +0200
Organization A noiseless patient Spider
Message-ID <msal0b$udo$1@dont-email.me> (permalink)
References (9 earlier) <2015Sep3.123542@mips.complang.tuwien.ac.at> <ms9jb8$fre$1@dont-email.me> <2015Sep3.181126@mips.complang.tuwien.ac.at> <msa991$ga4$1@dont-email.me> <877fo7gqvv.fsf@jester.gateway.sonic.net>

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Paul Rubin wrote:

> Bernd Paysan <bernd.paysan@gmx.de> writes:
>> No, the main problem is telling the other thread that there is some data
>> for
>> it.  That's using an OS IPC call, and that takes several thousand cycles.
>> You can pass around a lot of data between the cores; that works well.
> 
> In the uncontended case you check a futex in user space and proceed if
> there's something to do, or yield to the kernel if there's nothing to
> do.  There's only IPC overhead if there's contention in which case you
> have to make a system call.

Unfortunately, the contention is the rule, and the uncontented case the 
exception.  The problem of asynchronous tasks is that either the producer or 
the consumer waits, and that's the contented case.  So either the producer 
has to tell the consumer "good morning, time to wake up, I've some new data 
for you", or the consumer says "good afternoon, producer, stop napping, and 
give me another chunk of data".

In a non-trivial parallel program, you have tasks which run short, and tasks 
which run longer, joins where you wait for all inputs to compilete, and so 
on.  This only works well if the context switch and wake/sleep IPC by itself 
is a lightweight operation.

-- 
Bernd Paysan
"If you want it done right, you have to do it yourself"
net2o ID: kQusJzA;7*?t=uy@X}1GWr!+0qqp_Cn176t4(dQ*
http://bernd-paysan.de/

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GA144 use cases dunno <dunno@dunno.dunno> - 2015-08-31 07:20 +0000
  Re: GA144 use cases rickman <gnuarm@gmail.com> - 2015-08-31 09:55 -0400
  Re: GA144 use cases Syd Rumpo <usenet@nononono.co.uk> - 2015-08-31 16:49 +0100
    Re: GA144 use cases rickman <gnuarm@gmail.com> - 2015-08-31 18:35 -0400
  Re: GA144 use cases Dennis Ruffer <daruffer@gmail.com> - 2015-08-31 19:08 -0700
    Re: GA144 use cases Mux <Yvo.Zoer@gmail.com> - 2015-09-02 10:57 -0700
      Re: GA144 use cases rickman <gnuarm@gmail.com> - 2015-09-02 14:17 -0400
        Re: GA144 use cases Mux <Yvo.Zoer@gmail.com> - 2015-09-02 11:28 -0700
          Re: GA144 use cases hughaguilar96@gmail.com - 2015-09-02 13:41 -0700
          Re: GA144 use cases rickman <gnuarm@gmail.com> - 2015-09-02 16:50 -0400
            Re: GA144 use cases Mux <Yvo.Zoer@gmail.com> - 2015-09-02 15:03 -0700
              Re: GA144 use cases rickman <gnuarm@gmail.com> - 2015-09-02 18:18 -0400
                Re: GA144 use cases Mux <Yvo.Zoer@gmail.com> - 2015-09-02 16:14 -0700
                Re: GA144 use cases rickman <gnuarm@gmail.com> - 2015-09-02 20:40 -0400
                Re: GA144 use cases Greg <borota@gmail.com> - 2015-09-02 17:53 -0700
                Re: GA144 use cases rickman <gnuarm@gmail.com> - 2015-09-02 21:25 -0400
                Re: GA144 use cases Mux <Yvo.Zoer@gmail.com> - 2015-09-02 22:28 -0700
                Re: GA144 use cases Paul Rubin <no.email@nospam.invalid> - 2015-09-02 22:53 -0700
                Re: GA144 use cases rickman <gnuarm@gmail.com> - 2015-09-03 11:32 -0400
                Re: GA144 use cases Paul Rubin <no.email@nospam.invalid> - 2015-09-03 11:57 -0700
                Re: GA144 use cases anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2015-09-03 10:35 +0000
                Re: GA144 use cases Bernd Paysan <bernd.paysan@gmx.de> - 2015-09-03 15:54 +0200
                Re: GA144 use cases anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2015-09-03 16:11 +0000
                Re: GA144 use cases rickman <gnuarm@gmail.com> - 2015-09-03 13:06 -0400
                Re: GA144 use cases anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2015-09-04 08:07 +0000
                Re: GA144 use cases rickman <gnuarm@gmail.com> - 2015-09-04 11:49 -0400
                Re: GA144 use cases anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2015-09-05 11:06 +0000
                Re: GA144 use cases Paul Rubin <no.email@nospam.invalid> - 2015-09-05 09:05 -0700
                Re: GA144 use cases rickman <gnuarm@gmail.com> - 2015-09-05 12:59 -0400
                Re: GA144 use cases mhx@iae.nl - 2015-09-05 10:56 -0700
                Re: GA144 use cases anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2015-09-06 14:29 +0000
                Re: GA144 use cases Bernd Paysan <bernd.paysan@gmx.de> - 2015-09-03 22:08 +0200
                Re: GA144 use cases Paul Rubin <no.email@nospam.invalid> - 2015-09-03 14:00 -0700
                Re: GA144 use cases Bernd Paysan <bernd.paysan@gmx.de> - 2015-09-04 01:28 +0200
                Re: GA144 use cases franck.bensusan@gmail.com - 2015-09-03 23:04 -0700
                Re: GA144 use cases anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2015-09-04 08:24 +0000
                Re: GA144 use cases Bernd Paysan <bernd.paysan@gmx.de> - 2015-09-04 15:09 +0200
                Re: GA144 use cases anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2015-09-05 15:10 +0000
                Re: GA144 use cases Bernd Paysan <bernd.paysan@gmx.de> - 2015-09-05 22:04 +0200
                Re: GA144 use cases anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2015-09-06 14:51 +0000
                Re: GA144 use cases Bernd Paysan <bernd.paysan@gmx.de> - 2015-09-06 22:51 +0200
                Re: GA144 use cases Greg <borota@gmail.com> - 2015-09-06 17:30 -0700
                Re: GA144 use cases Paul Rubin <no.email@nospam.invalid> - 2015-09-04 22:27 -0700
                Re: GA144 use cases Bernd Paysan <bernd.paysan@gmx.de> - 2015-09-05 13:07 +0200
                Re: GA144 use cases anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2015-09-05 11:22 +0000
                Re: GA144 use cases anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2015-09-04 08:14 +0000
                Re: GA144 use cases Bernd Paysan <bernd.paysan@gmx.de> - 2015-09-04 15:13 +0200
                Re: GA144 use cases anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2015-09-05 16:06 +0000
                Re: GA144 use cases Bernd Paysan <bernd.paysan@gmx.de> - 2015-09-05 21:05 +0200
                Re: GA144 use cases anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2015-09-06 14:37 +0000
                Re: GA144 use cases Andrew Haley <andrew29@littlepinkcloud.invalid> - 2015-11-30 04:17 -0600
                Re: GA144 use cases Bernd Paysan <bernd.paysan@gmx.de> - 2015-12-01 23:06 +0100
                Re: GA144 use cases Mark Wills <markwills1970@gmail.com> - 2015-09-03 00:05 -0700
                Re: GA144 use cases rickman <gnuarm@gmail.com> - 2015-09-03 13:08 -0400
              Re: GA144 use cases forther <forther@gmail.com> - 2015-09-07 11:26 -0700
      Re: GA144 use cases rickman <gnuarm@gmail.com> - 2015-09-02 15:15 -0400
    Re: GA144 use cases forther <forther@gmail.com> - 2015-09-07 11:21 -0700
      Re: GA144 use cases rickman <gnuarm@gmail.com> - 2015-11-30 16:33 -0500
        Re: GA144 use cases forther <forther@gmail.com> - 2015-12-03 12:12 -0800
          Re: GA144 use cases rickman <gnuarm@gmail.com> - 2015-12-03 16:10 -0500
  Re: GA144 use cases Jason Damisch <jasondamisch@yahoo.com> - 2015-09-02 12:10 -0700
  Re: GA144 use cases Stefan Mauerhofer <smauerhofer@androsoft.ch> - 2015-09-03 01:27 -0700
    Re: GA144 use cases Syd Rumpo <usenet@nononono.co.uk> - 2015-09-03 13:32 +0100
      Re: GA144 use cases rickman <gnuarm@gmail.com> - 2015-09-03 11:32 -0400
  Re: GA144 use cases mhx@iae.nl (Marcel Hendrix) - 2015-09-03 18:57 +0200
    Re: GA144 use cases Bernd Paysan <bernd.paysan@gmx.de> - 2015-09-03 23:58 +0200
    Re: GA144 use cases anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2015-09-04 07:52 +0000
    Re: GA144 use cases Waldek Hebisch <hebisch@antispam.uni.wroc.pl> - 2015-09-05 16:32 +0000
      Re: GA144 use cases mhx@iae.nl - 2015-09-05 10:52 -0700
        Re: GA144 use cases Bernd Paysan <bernd.paysan@gmx.de> - 2015-09-05 22:11 +0200
          Re: GA144 use cases anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2015-09-06 14:18 +0000
            Re: GA144 use cases anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2015-09-07 07:49 +0000
        Re: GA144 use cases Waldek Hebisch <hebisch@math.uni.wroc.pl> - 2015-09-05 23:42 +0000
          Re: GA144 use cases Paul Rubin <no.email@nospam.invalid> - 2015-09-05 17:25 -0700
  Re: GA144 use cases Stefan Mauerhofer <smauerhofer@androsoft.ch> - 2015-09-07 03:18 -0700
    Re: GA144 use cases Raimond Dragomir <raimond.dragomir@gmail.com> - 2015-09-07 03:31 -0700
      Re: GA144 use cases rickman <gnuarm@gmail.com> - 2015-09-07 15:06 -0400
        Re: GA144 use cases Stefan Mauerhofer <smauerhofer@androsoft.ch> - 2015-09-08 21:41 -0700
          Re: GA144 use cases rickman <gnuarm@gmail.com> - 2015-09-09 02:54 -0400
            Re: GA144 use cases Stefan Mauerhofer <smauerhofer@androsoft.ch> - 2015-09-09 03:02 -0700
              Re: GA144 use cases rickman <gnuarm@gmail.com> - 2015-09-09 16:55 -0400
                Re: GA144 use cases Paul Rubin <no.email@nospam.invalid> - 2015-09-09 20:12 -0700
                Re: GA144 use cases rickman <gnuarm@gmail.com> - 2015-09-09 23:40 -0400
                Re: GA144 use cases rickman <gnuarm@gmail.com> - 2015-09-09 23:43 -0400
                Re: GA144 use cases rickman <gnuarm@gmail.com> - 2015-09-10 00:07 -0400
                Re: GA144 use cases Stefan Mauerhofer <smauerhofer@androsoft.ch> - 2015-09-09 21:55 -0700
                Re: GA144 use cases rickman <gnuarm@gmail.com> - 2015-09-10 01:43 -0400
                Re: GA144 use cases Stefan Mauerhofer <smauerhofer@androsoft.ch> - 2015-09-09 23:49 -0700
                Re: GA144 use cases rickman <gnuarm@gmail.com> - 2015-09-10 14:43 -0400
                Re: GA144 use cases rickman <gnuarm@gmail.com> - 2015-09-10 16:10 -0400
                Re: GA144 use cases Stefan Mauerhofer <smauerhofer@androsoft.ch> - 2015-09-12 03:15 -0700
                Re: GA144 use cases rickman <gnuarm@gmail.com> - 2015-09-12 10:28 -0400
                Re: GA144 use cases Greg <abiforth@gmail.com> - 2015-09-13 13:05 -0700
                Re: GA144 use cases rickman <gnuarm@gmail.com> - 2015-09-13 18:59 -0400
                Re: GA144 use cases Greg <abiforth@gmail.com> - 2015-09-13 18:42 -0700
                Re: GA144 use cases rickman <gnuarm@gmail.com> - 2015-09-13 22:47 -0400
                Re: GA144 use cases Greg <abiforth@gmail.com> - 2015-09-13 21:24 -0700
                Re: GA144 use cases rickman <gnuarm@gmail.com> - 2015-09-14 02:00 -0400
                Re: GA144 use cases borota@gmail.com - 2015-09-14 08:35 -0700
                Re: GA144 use cases rickman <gnuarm@gmail.com> - 2015-09-14 12:06 -0400
                Re: GA144 use cases borota@gmail.com - 2015-09-14 09:33 -0700
                Re: GA144 use cases rickman <gnuarm@gmail.com> - 2015-09-14 13:25 -0400
                Re: GA144 use cases Greg <borota@gmail.com> - 2015-09-14 14:17 -0700
                Re: GA144 use cases rickman <gnuarm@gmail.com> - 2015-09-14 18:12 -0400
                Re: GA144 use cases Greg <schmegner@gmail.com> - 2015-09-14 18:15 -0700
                Re: GA144 use cases rickman <gnuarm@gmail.com> - 2015-09-14 22:16 -0400
                Re: GA144 use cases Greg <borota@gmail.com> - 2015-09-18 14:50 -0700
                Re: GA144 use cases Jason Damisch <jasondamisch@yahoo.com> - 2015-09-18 15:11 -0700
                Re: GA144 use cases Greg <borota@gmail.com> - 2015-09-19 05:32 -0700
                Re: GA144 use cases Dennis Ruffer <daruffer@gmail.com> - 2015-09-19 08:39 -0700
                Re: GA144 use cases Greg <borota@gmail.com> - 2015-09-20 19:03 -0700
                Re: GA144 use cases Dennis Ruffer <daruffer@gmail.com> - 2015-09-21 06:44 -0700
                Re: GA144 use cases Dennis Ruffer <daruffer@gmail.com> - 2015-09-22 13:10 -0700
                Re: GA144 use cases Mark Wills <markwills1970@gmail.com> - 2015-09-18 16:18 -0700
                Re: GA144 use cases schmegner@gmail.com - 2015-09-14 18:21 -0700

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