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Groups > comp.lang.forth > #41718
| From | anton@mips.complang.tuwien.ac.at (Anton Ertl) |
|---|---|
| Newsgroups | comp.lang.forth |
| Subject | Re: GA144 use cases |
| Date | 2015-09-04 08:14 +0000 |
| Organization | Institut fuer Computersprachen, Technische Universitaet Wien |
| Message-ID | <2015Sep4.101402@mips.complang.tuwien.ac.at> (permalink) |
| References | (7 earlier) <34f1f225-c6e9-47e7-91cb-ba225d5d9bca@googlegroups.com> <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> |
Bernd Paysan <bernd.paysan@gmx.de> writes:
>Anton Ertl wrote:
>> If it's just communication, that can go pretty fast through shared
>> memory; on a single-socket multi-core CPU, that's a trip through the
>> L3 cache (<100 cycles latency for the first cache line; and you can
>> communicate pretty long blocks with pretty low additional overhead).
>
>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.
That's synchronization, and you don't need to to that through the OS,
you can also use the user level. Unfortunately, I don't know of a
user-level portable library for this stuff.
>> If you manage to use large blocks and synchronization is rare, you can
>> make good use of multiple cores. OTOH, if you need to create lots of
>> short-running tasks and combine their results, you will probably see a
>> lot of overhead.
>
>Yes, and that's the problem. There are a lot of low-hanging fruits for
>parallelization which are short-running tasks.
However, even for that you do not need OS-level synchronization for
every task: the boss can set up lots of tasks, and each worker thread
takes a task, performs it, then calls the per-thread scheduler, which
takes and performs the next task. If there are many short tasks, a
whole batch of them should be assigned to one worker to reduce
synchronization overhead between workers.
>> You can get that by mmap()ing the memory once read-only and once
>> read/write. If you want to mmapt them to the same address, I think
>> you need to do that in two different processes.
>
>Multiple threads in one process all see the same mapping. It works between
>different processes, because they have different page tables.
Yes, so if you want different permissions for threads of one process,
you need to map the same thing two times (at different addresses),
once read-write and once read-only.
- anton
--
M. Anton Ertl http://www.complang.tuwien.ac.at/anton/home.html
comp.lang.forth FAQs: http://www.complang.tuwien.ac.at/forth/faq/toc.html
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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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