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| Newsgroups | comp.arch |
|---|---|
| Subject | Re: Notions of Time in Computer Architecture |
| References | <4E0BA344.6000003@SPAM.comp-arch.net> <6s5ud8-ikv2.ln1@ntp6.tmsw.no> |
| From | Morten Reistad <first@last.name> |
| Date | 2011-06-30 18:19 +0200 |
| Message-ID | <4e0cae63$1@news.broadpark.no> (permalink) |
In article <6s5ud8-ikv2.ln1@ntp6.tmsw.no>, Terje Mathisen <"terje.mathisen at tmsw.no"> wrote: >Andy "Krazy" Glew wrote: >> First, there is [[real time]] or [[wall clock time]]. Time in the real >> world (forgetting Einsteinian relativistic issues for the moment). > >With the sub-ns time scales in modern cpus, any large cluster (even if >presented as a single image CC-NUMA system to the programmer) will get >into trouble here: You don't need to invoke NUMA. Even a single processor is a stretch to keep under harmonius time, and we have stayed at the edge of what is possible to synchronise ever since the KA10 (1967). As they get smaller, they also get faster. >You cannot have a globally consistent, totally distributed clock: Unless >you designate a single point of control, there's no way to always be >able to figure out the absolute order of two or more distributed events, >right? > >You simply have to fall back on workarounds, like having N bits for the >clock, of which the lower M bits is the clock ID. This way all >timestamps will be globally unique and sortable, even if the resulting >order might not be the "real" order as observed by some omniscient entity. This ordering problem crept up on the financial markets ca 1985, and has never been resolved. Financial transactions do not rely on timestamps for this reason, they just have a unique ID. -- mrr
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Notions of Time in Computer Architecture "Andy \"Krazy\" Glew" <andy@SPAM.comp-arch.net> - 2011-06-29 15:12 -0700
Re: Notions of Time in Computer Architecture Robert Myers <rbmyersusa@gmail.com> - 2011-06-29 22:08 -0400
Re: Notions of Time in Computer Architecture Terje Mathisen <"terje.mathisen at tmsw.no"> - 2011-06-30 14:13 +0200
Re: Notions of Time in Computer Architecture Morten Reistad <first@last.name> - 2011-06-30 18:19 +0200
Re: Notions of Time in Computer Architecture ChrisQ <meru@devnull.com> - 2011-06-30 21:23 +0100
Re: Notions of Time in Computer Architecture Rick Jones <rick.jones2@hp.com> - 2011-06-30 19:42 +0000
Re: Notions of Time in Computer Architecture Terje Mathisen <"terje.mathisen at tmsw.no"> - 2011-07-01 10:46 +0200
Re: Notions of Time in Computer Architecture Rick Jones <rick.jones2@hp.com> - 2011-07-01 15:17 +0000
Re: Notions of Time in Computer Architecture ChrisQ <meru@devnull.com> - 2011-07-04 16:51 +0100
Re: Notions of Time in Computer Architecture nmm1@cam.ac.uk - 2011-07-01 05:54 +0100
Re: Notions of Time in Computer Architecture "Andy \"Krazy\" Glew" <andy@SPAM.comp-arch.net> - 2011-06-30 22:42 -0700
Re: Notions of Time in Computer Architecture jsavard@excxn.aNOSPAMb.cdn.invalid (John Savard) - 2011-07-01 20:16 +0000
Re: Notions of Time in Computer Architecture Terje Mathisen <"terje.mathisen at tmsw.no"> - 2011-07-02 10:33 +0200
Re: Notions of Time in Computer Architecture nmm1@cam.ac.uk - 2011-07-02 09:26 +0100
Re: Notions of Time in Computer Architecture jsavard@excxn.aNOSPAMb.cdn.invalid (John Savard) - 2011-07-02 12:40 +0000
Re: Notions of Time in Computer Architecture nmm1@cam.ac.uk - 2011-07-02 16:14 +0100
Re: Notions of Time in Computer Architecture Robert Myers <rbmyersusa@gmail.com> - 2011-07-02 16:48 -0400
Re: Notions of Time in Computer Architecture Quadibloc <jsavard@ecn.ab.ca> - 2011-07-02 14:27 -0700
Re: Notions of Time in Computer Architecture Stephen Sprunk <stephen@sprunk.org> - 2011-07-03 15:07 -0500
Re: Notions of Time in Computer Architecture Terje Mathisen <"terje.mathisen at tmsw.no"> - 2011-07-04 08:15 +0200
Re: Notions of Time in Computer Architecture Morten Reistad <first@last.name> - 2011-07-04 17:50 +0200
Re: Notions of Time in Computer Architecture Terje Mathisen <"terje.mathisen at tmsw.no"> - 2011-07-04 21:21 +0200
Re: Notions of Time in Computer Architecture Robert Wessel <robertwessel2@yahoo.com> - 2011-07-04 23:44 -0500
Re: Notions of Time in Computer Architecture Terje Mathisen <"terje.mathisen at tmsw.no"> - 2011-07-05 07:51 +0200
Re: Notions of Time in Computer Architecture Robert Wessel <robertwessel2@yahoo.com> - 2011-07-05 01:56 -0500
Re: Notions of Time in Computer Architecture Morten Reistad <first@last.name> - 2011-07-03 19:28 +0200
Re: Notions of Time in Computer Architecture "Andy \"Krazy\" Glew" <andy@SPAM.comp-arch.net> - 2011-07-03 11:27 -0700
Re: Notions of Time in Computer Architecture nmm1@cam.ac.uk - 2011-07-03 22:13 +0100
Re: Notions of Time in Computer Architecture "Andy \"Krazy\" Glew" <andy@SPAM.comp-arch.net> - 2011-07-03 18:53 -0700
Re: Notions of Time in Computer Architecture nmm1@cam.ac.uk - 2011-07-04 08:34 +0100
Re: Notions of Time in Computer Architecture "Andy \"Krazy\" Glew" <andy@SPAM.comp-arch.net> - 2011-07-03 18:51 -0700
Re: Notions of Time in Computer Architecture anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2011-07-04 09:20 +0000
Re: Notions of Time in Computer Architecture Robert Myers <rbmyersusa@gmail.com> - 2011-07-04 12:26 -0700
Re: Notions of Time in Computer Architecture EricP <ThatWouldBeTelling@thevillage.com> - 2011-07-04 19:35 -0400
Re: Notions of Time in Computer Architecture Bernd Paysan <bernd.paysan@gmx.de> - 2011-07-08 15:48 +0200
Re: Notions of Time in Computer Architecture Michael S <already5chosen@yahoo.com> - 2011-07-05 15:24 -0700
Re: Notions of Time in Computer Architecture "Andy \"Krazy\" Glew" <andy@SPAM.comp-arch.net> - 2011-07-08 09:25 -0700
Re: Notions of Time in Computer Architecture Robert Myers <rbmyersusa@gmail.com> - 2011-07-08 12:12 -0700
Re: Notions of Time in Computer Architecture "Andy \"Krazy\" Glew" <andy@SPAM.comp-arch.net> - 2011-07-08 17:27 -0700
Re: Notions of Time in Computer Architecture Robert Myers <rbmyersusa@gmail.com> - 2011-07-09 18:07 -0400
Re: Notions of Time in Computer Architecture EricP <ThatWouldBeTelling@thevillage.com> - 2011-07-10 12:03 -0400
Re: Notions of Time in Computer Architecture Robert Myers <rbmyersusa@gmail.com> - 2011-07-10 13:02 -0700
Re: Notions of Time in Computer Architecture Bernd Paysan <bernd.paysan@gmx.de> - 2011-07-08 15:13 +0200
Re: Notions of Time in Computer Architecture Gubbi <gubsan100@hotmail.com> - 2011-07-01 00:50 -0700
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