Path: csiph.com!x330-a1.tempe.blueboxinc.net!usenet.pasdenom.info!news.albasani.net!eternal-september.org!feeder.eternal-september.org!.POSTED!not-for-mail From: Alexander Terekhov Newsgroups: comp.programming.threads Subject: Re: questions about memory_order_seq_cst fence Date: Tue, 21 Jun 2011 15:59:44 +0200 Organization: A noiseless patient Spider Lines: 22 Message-ID: <4E00A3D0.82D8E955@web.de> References: <43eb372b-6517-4914-b647-860f1f7136ba@k15g2000pri.googlegroups.com> <87tybsm5kq.fsf@justsoftwaresolutions.co.uk> <35ec803e-2871-41ce-97ea-8b615b29050f@r33g2000prh.googlegroups.com> <87hb7r5z03.fsf@justsoftwaresolutions.co.uk> <87fwnafd9j.fsf@justsoftwaresolutions.co.uk> <4358686f-7bfb-480e-ae71-a8ce57566ab0@l14g2000pro.googlegroups.com> <871uyuasc0.fsf@justsoftwaresolutions.co.uk> <4DFCAB39.35CDACC8@web.de> <87oc1ssyaq.fsf@justsoftwaresolutions.co.uk> <4DFF4B71.20A46979@web.de> <871uyosiuw.fsf@justsoftwaresolutions.co.uk> Reply-To: terekhov@web.de Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Injection-Info: mx04.eternal-september.org; posting-host="MCbSEzW5qwGLFMNXJh39IQ"; logging-data="18705"; mail-complaints-to="abuse@eternal-september.org"; posting-account="U2FsdGVkX18H0lFV7H5XAUaZUZKl/WMDzPEYzApmsAM=" X-Mailer: Mozilla 4.77 [en] (Windows NT 5.0; U) X-Accept-Language: en Cancel-Lock: sha1:M9hGrTEhskOjbVC+yUgpNtk5zcY= Xref: x330-a1.tempe.blueboxinc.net comp.programming.threads:344 Anthony Williams wrote: [... remote write atomicity ...] > However, in particular cases then you can order particular subsets. If > you have an example of code that you would like to work then I can see > if I can think of a way to make it work without using seq_cst everywhere. See examples in http://portal.acm.org/citation.cfm?id=1375591 ("4.2 Unintended Consequences of Relaxing Write-Atomicity") "4.2.1 Write-to-Read Causality (WRC) Must be Upheld" "4.2.2 Read-to-Write Causality (RWC)" "4.2.3 Subtle Interplay Between Coherence and Causality" regards, alexander.