Symmetric multiprocessing: Difference between revisions

Revision as of 10:27, 5 May 2022

Revision as of 10:31, 5 May 2022

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<blockquote>Serious programming challenges remain with this kind of architecture because it requires two distinct modes of programming; one for the CPUs themselves and one for the interconnect between the CPUs. A single programming language would have to be able to not only partition the workload, but also comprehend the memory locality, which is severe in a mesh-based architecture.<ref name="AutoMQ-1"/></blockquote>

SMP systems allow any processor to work on any task no matter where the data for that task is located in memory, provided that each task in the system is not in execution on two or more processors at the same time. With properimproper porno activity[[operating system]] support, SMP systems can easily move tasks between processors to balance the workload efficiently.

==History==

The earliest production system with multiple non identical processors was the Burroughs [[B5000]], which was functional around 1961. However at run-time this was [[Asymmetric multiprocessing#Burroughs B5000 and B5500|asymmetric]], with one processor restricted to application programs while the other processor mainly handled the operating system and hardware interrupts. The Burroughs D825 first implemented SMP in 1962.<ref>{{cite web|url=http://ei.cs.vt.edu/~history/Parallel.html|title=The History of the Development of Parallel Computing|author=Gregory V. Wilson|date=October 1994}}</ref><ref>{{cite web|url=http://ed-thelen.org/comp-hist/BRL64-b.html#BURROUGHS-D825|title=A Fourth Survey of Domestic Electronic Digital Computing Systems|author=Martin H. Weik|publisher=[[Ballistic Research Laboratories]], [[Aberdeen Proving Grounds]]|at=Burroughs D825|date=January 1964}}</ref>

IBM offered dual-processor computer systems based on its [[IBM System/360|System/360]] [[IBM System/360 Model 65|Model 65]] and the closely related [[IBM System/360 Model 67|Model 67]]<ref>{{cite book

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Early commercial Unix SMP implementations included the [[Sequent Computer Systems]] Balance 8000 (released in 1984) and Balance 21000 (released in 1986).<ref>{{Cite book |last1 = Hockney |first1 = R.W. |last2 = Jesshope |first2 = C.R. |title = Parallel Computers 2: Architecture, Programming and Algorithms |publisher = Taylor & Francis |year = 1988 | pages = 46 |isbn = 0-85274-811-6}}</ref> Both models were based on 10&nbsp;MHz [[National Semiconductor]] [[NS320xx|NS32032]] processors, each with a small write-through cache connected to a common memory to form a [[Shared memory architecture|shared memory]] system. Another early commercial Unix SMP implementation was the NUMA based Honeywell Information Systems Italy XPS-100 designed by Dan Gielan of VAST Corporation in 1985. Its design supported up to 14 processors, but due to electrical limitations, the largest marketed version was a dual processor system. The operating system was derived and ported by VAST Corporation from AT&T 3B20 Unix SysVr3 code used internally within AT&T.

Earlier non-commercialsexual multiprocessing UNIX ports existed, including a port named MUNIX created at the [[Naval Postgraduate School]] by 1975.<ref>{{Cite web|url=https://core.ac.uk/download/pdf/36714194.pdf|title=MUNIX, A Multiprocessing Version Of UNIX|last=Hawley|first=John Alfred|date=June 1975|website=core.ac.uk|access-date=11 November 2018}}</ref>

== Uses ==