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Groups > comp.programming.threads > #291
| From | Anthony Williams <anthony.ajw@gmail.com> |
|---|---|
| Newsgroups | comp.programming.threads |
| Subject | Re: questions about memory_order_seq_cst fence |
| References | (1 earlier) <it5sht$i7j$1@node2.news.atman.pl> <b7657dae-d49f-4859-8020-b5d76bfae2cd@p9g2000prh.googlegroups.com> <itbb7k$uhh$1@node2.news.atman.pl> <87boxyfctc.fsf@justsoftwaresolutions.co.uk> <4DF9D581.E607BEB4@web.de> |
| Date | 2011-06-16 11:19 +0100 |
| Message-ID | <8739jaf59n.fsf@justsoftwaresolutions.co.uk> (permalink) |
| Organization | CNNTP |
Alexander Terekhov <terekhov@web.de> writes: > Anthony Williams wrote: >> >> Edek <edek.pienkowski@gmail.com> writes: >> >> > As a side note, I compiled all ops on x86_64, and atomic<int>::load >> > is mfence/load/mfence even for relaxed. I'd need some time to analyse >> > the thing from perspective of other ops implementations in all >> > orderings, and this leads me to the not so subtle question: >> >> Ouch. That is a seriously over-cautious implementation. Atomics should >> not need any fences on x86_64 unless you actually write >> atomic_thread_fence(memory_order_seq_cst) >> >> See my blog entry for the required operations: >> >> http://www.justsoftwaresolutions.co.uk/threading/intel-memory-ordering-and-c++-memory-model.html >> >> The only one that is not a plain MOV is a seq_cst store, which is an >> XCHG. > > I believe that a seq_cst load is not a plain move either... Why do think it shouldn't be, and what do you think it should be instead? The mapping in my blog post was confirmed by Intel processor engineers. Anthony -- Author of C++ Concurrency in Action http://www.stdthread.co.uk/book/ just::thread C++0x thread library http://www.stdthread.co.uk Just Software Solutions Ltd http://www.justsoftwaresolutions.co.uk 15 Carrallack Mews, St Just, Cornwall, TR19 7UL, UK. Company No. 5478976
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questions about memory_order_seq_cst fence Masakuni Oishi <yamasa@bsdhouse.org> - 2011-06-13 09:40 -0700
Re: questions about memory_order_seq_cst fence Edek <edek.pienkowski@gmail.com> - 2011-06-13 22:39 +0200
Re: questions about memory_order_seq_cst fence Masakuni Oishi <yamasa@bsdhouse.org> - 2011-06-14 08:27 -0700
Re: questions about memory_order_seq_cst fence Edek <edek.pienkowski@gmail.com> - 2011-06-16 00:21 +0200
Re: questions about memory_order_seq_cst fence Joshua Maurice <joshuamaurice@gmail.com> - 2011-06-15 15:48 -0700
Re: questions about memory_order_seq_cst fence Masakuni Oishi <yamasa@bsdhouse.org> - 2011-06-16 05:03 -0700
Re: questions about memory_order_seq_cst fence Anthony Williams <anthony.ajw@gmail.com> - 2011-06-16 08:35 +0100
Re: questions about memory_order_seq_cst fence Alexander Terekhov <terekhov@web.de> - 2011-06-16 12:05 +0200
Re: questions about memory_order_seq_cst fence Anthony Williams <anthony.ajw@gmail.com> - 2011-06-16 11:19 +0100
Re: questions about memory_order_seq_cst fence Alexander Terekhov <terekhov@web.de> - 2011-06-16 13:57 +0200
Re: questions about memory_order_seq_cst fence Anthony Williams <anthony.ajw@gmail.com> - 2011-06-16 13:51 +0100
Re: questions about memory_order_seq_cst fence Alexander Terekhov <terekhov@web.de> - 2011-06-16 16:53 +0200
Re: questions about memory_order_seq_cst fence Anthony Williams <anthony.ajw@gmail.com> - 2011-06-16 16:17 +0100
Re: questions about memory_order_seq_cst fence Alexander Terekhov <terekhov@web.de> - 2011-06-16 17:37 +0200
Re: questions about memory_order_seq_cst fence "Chris M. Thomasson" <cristom@charter.net> - 2011-06-16 08:47 -0700
Re: questions about memory_order_seq_cst fence Anthony Williams <anthony.ajw@gmail.com> - 2011-06-16 16:54 +0100
Re: questions about memory_order_seq_cst fence "Chris M. Thomasson" <cristom@charter.net> - 2011-06-16 09:01 -0700
Re: questions about memory_order_seq_cst fence Anthony Williams <anthony.ajw@gmail.com> - 2011-06-16 17:07 +0100
Re: questions about memory_order_seq_cst fence "Chris M. Thomasson" <cristom@charter.net> - 2011-06-16 13:59 -0700
Re: questions about memory_order_seq_cst fence Joshua Maurice <joshuamaurice@gmail.com> - 2011-06-16 14:32 -0700
Re: questions about memory_order_seq_cst fence Anthony Williams <anthony.ajw@gmail.com> - 2011-06-17 08:03 +0100
Re: questions about memory_order_seq_cst fence Alexander Terekhov <terekhov@web.de> - 2011-06-17 16:19 +0200
Re: questions about memory_order_seq_cst fence Anthony Williams <anthony.ajw@gmail.com> - 2011-06-17 15:40 +0100
Re: questions about memory_order_seq_cst fence Alexander Terekhov <terekhov@web.de> - 2011-06-30 14:26 +0200
Re: questions about memory_order_seq_cst fence "Chris M. Thomasson" <cristom@charter.net> - 2011-06-17 15:24 -0700
Re: questions about memory_order_seq_cst fence Joshua Maurice <joshuamaurice@gmail.com> - 2011-06-18 03:49 -0700
Re: questions about memory_order_seq_cst fence "Chris M. Thomasson" <cristom@charter.net> - 2011-06-18 14:40 -0700
Re: questions about memory_order_seq_cst fence Joshua Maurice <joshuamaurice@gmail.com> - 2011-06-18 15:46 -0700
Re: questions about memory_order_seq_cst fence "Chris M. Thomasson" <cristom@charter.net> - 2011-06-18 20:27 -0700
Re: questions about memory_order_seq_cst fence Joshua Maurice <joshuamaurice@gmail.com> - 2011-06-18 21:31 -0700
Re: questions about memory_order_seq_cst fence Joshua Maurice <joshuamaurice@gmail.com> - 2011-06-18 21:37 -0700
Re: questions about memory_order_seq_cst fence "Chris M. Thomasson" <cristom@charter.net> - 2011-06-20 15:45 -0700
Re: questions about memory_order_seq_cst fence Joshua Maurice <joshuamaurice@gmail.com> - 2011-06-20 20:05 -0700
Re: questions about memory_order_seq_cst fence Alexander Terekhov <terekhov@web.de> - 2011-06-18 14:06 +0200
Re: questions about memory_order_seq_cst fence Alexander Terekhov <terekhov@web.de> - 2011-06-16 18:32 +0200
Re: questions about memory_order_seq_cst fence "Chris M. Thomasson" <cristom@charter.net> - 2011-06-16 15:42 -0700
Re: questions about memory_order_seq_cst fence Edek <edek.pienkowski@gmail.com> - 2011-07-10 19:47 +0200
Re: questions about memory_order_seq_cst fence "Chris M. Thomasson" <cristom@charter.net> - 2011-06-16 08:51 -0700
Re: questions about memory_order_seq_cst fence Anthony Williams <anthony.ajw@gmail.com> - 2011-06-16 17:23 +0100
Re: questions about memory_order_seq_cst fence Alexander Terekhov <terekhov@web.de> - 2011-06-16 18:49 +0200
Re: questions about memory_order_seq_cst fence "Chris M. Thomasson" <cristom@charter.net> - 2011-06-16 08:51 -0700
Re: questions about memory_order_seq_cst fence Alexander Terekhov <terekhov@web.de> - 2011-06-16 17:25 +0200
Re: questions about memory_order_seq_cst fence Anthony Williams <anthony.ajw@gmail.com> - 2011-06-16 16:56 +0100
Re: questions about memory_order_seq_cst fence Alexander Terekhov <terekhov@web.de> - 2011-06-18 14:28 +0200
Re: questions about memory_order_seq_cst fence Anthony Williams <anthony.ajw@gmail.com> - 2011-06-20 09:54 +0100
Re: questions about memory_order_seq_cst fence Alexander Terekhov <terekhov@web.de> - 2011-06-20 15:39 +0200
Re: questions about memory_order_seq_cst fence Alexander Terekhov <terekhov@web.de> - 2011-06-22 13:24 +0200
Re: questions about memory_order_seq_cst fence Edek <edek.pienkowski@gmail.com> - 2011-06-16 14:39 +0200
Re: questions about memory_order_seq_cst fence Anthony Williams <anthony.ajw@gmail.com> - 2011-06-16 13:55 +0100
Re: questions about memory_order_seq_cst fence Alexander Terekhov <terekhov@web.de> - 2011-06-16 12:03 +0200
Re: questions about memory_order_seq_cst fence Edek <edek.pienkowski@gmail.com> - 2011-07-10 19:10 +0200
Re: questions about memory_order_seq_cst fence Joshua Maurice <joshuamaurice@gmail.com> - 2011-06-13 16:00 -0700
Re: questions about memory_order_seq_cst fence Joshua Maurice <joshuamaurice@gmail.com> - 2011-06-13 23:31 -0700
Re: questions about memory_order_seq_cst fence Masakuni Oishi <yamasa@bsdhouse.org> - 2011-06-14 08:32 -0700
Re: questions about memory_order_seq_cst fence Anthony Williams <anthony.ajw@gmail.com> - 2011-06-14 23:05 +0100
Re: questions about memory_order_seq_cst fence Joshua Maurice <joshuamaurice@gmail.com> - 2011-06-14 16:44 -0700
Re: questions about memory_order_seq_cst fence Anthony Williams <anthony.ajw@gmail.com> - 2011-06-15 08:34 +0100
Re: questions about memory_order_seq_cst fence Masakuni Oishi <yamasa@bsdhouse.org> - 2011-06-15 02:11 -0700
Re: questions about memory_order_seq_cst fence Joshua Maurice <joshuamaurice@gmail.com> - 2011-06-15 15:58 -0700
Re: questions about memory_order_seq_cst fence Anthony Williams <anthony.ajw@gmail.com> - 2011-06-16 08:26 +0100
Re: questions about memory_order_seq_cst fence Masakuni Oishi <yamasa@bsdhouse.org> - 2011-06-16 05:05 -0700
Re: questions about memory_order_seq_cst fence Anthony Williams <anthony.ajw@gmail.com> - 2011-06-16 13:11 +0100
Re: questions about memory_order_seq_cst fence Alexander Terekhov <terekhov@web.de> - 2011-06-18 15:42 +0200
Re: questions about memory_order_seq_cst fence Anthony Williams <anthony.ajw@gmail.com> - 2011-06-20 09:27 +0100
Re: questions about memory_order_seq_cst fence Alexander Terekhov <terekhov@web.de> - 2011-06-20 15:30 +0200
Re: questions about memory_order_seq_cst fence Anthony Williams <anthony.ajw@gmail.com> - 2011-06-20 15:00 +0100
Re: questions about memory_order_seq_cst fence Alexander Terekhov <terekhov@web.de> - 2011-06-21 14:54 +0200
Re: questions about memory_order_seq_cst fence Alexander Terekhov <terekhov@web.de> - 2011-06-21 18:37 +0200
Re: questions about memory_order_seq_cst fence Alexander Terekhov <terekhov@web.de> - 2011-06-21 15:59 +0200
Re: questions about memory_order_seq_cst fence Anthony Williams <anthony.ajw@gmail.com> - 2011-06-22 09:01 -0700
Re: questions about memory_order_seq_cst fence Anthony Williams <anthony.ajw@gmail.com> - 2011-06-20 15:41 +0100
Re: questions about memory_order_seq_cst fence Masakuni Oishi <yamasa@bsdhouse.org> - 2011-06-20 23:24 -0700
Re: questions about memory_order_seq_cst fence Masakuni Oishi <yamasa@bsdhouse.org> - 2011-06-22 10:46 -0700
Re: questions about memory_order_seq_cst fence Masakuni Oishi <yamasa@bsdhouse.org> - 2011-06-22 11:19 -0700
Re: questions about memory_order_seq_cst fence Masakuni Oishi <yamasa@bsdhouse.org> - 2011-06-22 11:57 -0700
Re: questions about memory_order_seq_cst fence Alexander Terekhov <terekhov@web.de> - 2011-06-27 14:05 +0200
Re: questions about memory_order_seq_cst fence Joshua Maurice <joshuamaurice@gmail.com> - 2011-06-29 16:14 -0700
Re: questions about memory_order_seq_cst fence Anthony Williams <anthony.ajw@gmail.com> - 2011-06-24 01:42 -0700
Re: questions about memory_order_seq_cst fence Alexander Terekhov <terekhov@web.de> - 2011-06-27 13:24 +0200
Re: questions about memory_order_seq_cst fence Anthony Williams <anthony.ajw@gmail.com> - 2011-07-01 02:25 -0700
Re: questions about memory_order_seq_cst fence Alexander Terekhov <terekhov@web.de> - 2011-07-01 12:48 +0200
Re: questions about memory_order_seq_cst fence Masakuni Oishi <yamasa@bsdhouse.org> - 2011-06-15 01:53 -0700
Re: questions about memory_order_seq_cst fence Joshua Maurice <joshuamaurice@gmail.com> - 2011-06-15 02:57 -0700
Re: questions about memory_order_seq_cst fence "Chris M. Thomasson" <cristom@charter.net> - 2011-06-15 02:06 -0700
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