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Groups > comp.arch.embedded > #26193
| From | David Brown <david.brown@hesbynett.no> |
|---|---|
| Newsgroups | comp.arch.embedded |
| Subject | Re: Speaking of Multiprocessing... |
| Date | 2017-03-24 09:17 +0100 |
| Organization | A noiseless patient Spider |
| Message-ID | <ob2khf$vd$1@dont-email.me> (permalink) |
| References | <ob1ij7$jja$1@dont-email.me> |
On 23/03/17 23:38, rickman wrote: > I recall a discussion about the design of an instruction set > architecture where someone was saying an instruction was required to > test and set a bit or word as an atomic operation if it was desired to > support multiple processors. Is this really true? Is this a function > that can't be emulated with other operations including the disabling of > interrupts? > There are many, many ways to implement synchronisation between threads, processors, whatever. In theory, they are mostly equivalent in that any one can be used to implement the others. In practice, there can be a lot of differences in the overheads in the hardware implementation, and the speed in practice. Typical implementations are "compare-and-swap" instructions (x86 uses these) and load-linked/store-conditional (common on RISC systems where instructions either load /or/ store, not both. And of course, on single processor systems there is always the "disable all interrupts" method. But if you can use dedicated hardware, there are many other methods. The XMOS devices have hardware support for pipelines and message passing. On a dual-core PPC device I used, there is a hardware block of semaphores. Each semaphore is a pair of 16-bit ID, 16-bit value that you can only access as a 32-bit read or write. You can write to it if the current ID is 0, or if the ID you are writing matches that of the semaphore. There is plenty of scope for variation based on that theme.
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Speaking of Multiprocessing... rickman <gnuarm@gmail.com> - 2017-03-23 18:38 -0400
Re: Speaking of Multiprocessing... Tim Wescott <seemywebsite@myfooter.really> - 2017-03-23 18:19 -0500
Re: Speaking of Multiprocessing... Don Y <blockedofcourse@foo.invalid> - 2017-03-23 16:26 -0700
Re: Speaking of Multiprocessing... Tim Wescott <seemywebsite@myfooter.really> - 2017-03-23 18:47 -0500
Re: Speaking of Multiprocessing... Don Y <blockedofcourse@foo.invalid> - 2017-03-23 17:49 -0700
Re: Speaking of Multiprocessing... upsidedown@downunder.com - 2017-03-24 09:48 +0200
Re: Speaking of Multiprocessing... Don Y <blockedofcourse@foo.invalid> - 2017-03-24 01:22 -0700
Re: Speaking of Multiprocessing... Clifford Heath <no.spam@please.net> - 2017-03-24 21:04 +1100
Re: Speaking of Multiprocessing... Robert Wessel <robertwessel2@yahoo.com> - 2017-03-24 22:01 -0500
Re: Speaking of Multiprocessing... Clifford Heath <no.spam@please.net> - 2017-03-25 18:49 +1100
Re: Speaking of Multiprocessing... Grant Edwards <invalid@invalid.invalid> - 2017-03-24 14:36 +0000
Re: Speaking of Multiprocessing... Robert Wessel <robertwessel2@yahoo.com> - 2017-03-23 22:43 -0500
Re: Speaking of Multiprocessing... rickman <gnuarm@gmail.com> - 2017-03-24 01:05 -0400
Re: Speaking of Multiprocessing... Robert Wessel <robertwessel2@yahoo.com> - 2017-03-24 00:37 -0500
Re: Speaking of Multiprocessing... rickman <gnuarm@gmail.com> - 2017-03-24 01:58 -0400
Re: Speaking of Multiprocessing... Robert Wessel <robertwessel2@yahoo.com> - 2017-03-24 02:07 -0500
Re: Speaking of Multiprocessing... rickman <gnuarm@gmail.com> - 2017-03-24 13:36 -0400
Re: Speaking of Multiprocessing... David Brown <david.brown@hesbynett.no> - 2017-03-24 19:06 +0100
Re: Speaking of Multiprocessing... rickman <gnuarm@gmail.com> - 2017-03-24 14:12 -0400
Re: Speaking of Multiprocessing... David Brown <david.brown@hesbynett.no> - 2017-03-25 01:48 +0100
Re: Speaking of Multiprocessing... rickman <gnuarm@gmail.com> - 2017-03-24 22:10 -0400
Re: Speaking of Multiprocessing... David Brown <david.brown@hesbynett.no> - 2017-03-25 15:25 +0100
Re: Speaking of Multiprocessing... rickman <gnuarm@gmail.com> - 2017-03-25 15:27 -0400
Re: Speaking of Multiprocessing... upsidedown@downunder.com - 2017-03-25 22:43 +0200
Re: Speaking of Multiprocessing... rickman <gnuarm@gmail.com> - 2017-03-25 17:06 -0400
Re: Speaking of Multiprocessing... David Brown <david.brown@hesbynett.no> - 2017-03-26 17:28 +0200
Re: Speaking of Multiprocessing... rickman <gnuarm@gmail.com> - 2017-03-26 13:27 -0400
Re: Speaking of Multiprocessing... Dimiter_Popoff <dp@tgi-sci.com> - 2017-03-25 00:42 +0200
Re: Speaking of Multiprocessing... rickman <gnuarm@gmail.com> - 2017-03-24 19:22 -0400
Re: Speaking of Multiprocessing... Rob Gaddi <rgaddi@highlandtechnology.invalid> - 2017-03-24 16:33 -0700
Re: Speaking of Multiprocessing... Robert Wessel <robertwessel2@yahoo.com> - 2017-03-24 22:47 -0500
Re: Speaking of Multiprocessing... Dimiter_Popoff <dp@tgi-sci.com> - 2017-03-25 12:40 +0200
Re: Speaking of Multiprocessing... Robert Wessel <robertwessel2@yahoo.com> - 2017-03-26 00:42 -0500
Re: Speaking of Multiprocessing... David Brown <david.brown@hesbynett.no> - 2017-03-24 09:17 +0100
Re: Speaking of Multiprocessing... Tom Gardner <spamjunk@blueyonder.co.uk> - 2017-03-24 09:28 +0000
Re: Speaking of Multiprocessing... David Brown <david.brown@hesbynett.no> - 2017-03-24 11:19 +0100
Re: Speaking of Multiprocessing... Tom Gardner <spamjunk@blueyonder.co.uk> - 2017-03-24 11:06 +0000
Re: Speaking of Multiprocessing... David Brown <david.brown@hesbynett.no> - 2017-03-24 12:21 +0100
Re: Speaking of Multiprocessing... Tom Gardner <spamjunk@blueyonder.co.uk> - 2017-03-24 16:09 +0000
Re: Speaking of Multiprocessing... David Brown <david.brown@hesbynett.no> - 2017-03-24 17:33 +0100
Re: Speaking of Multiprocessing... Tom Gardner <spamjunk@blueyonder.co.uk> - 2017-03-24 17:52 +0000
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