VIRTUAL PROCESSOR:
The term virtual processor or virtual processor core is used to identify each strand in a processor.Each virtual processor corresponds to a specific physical core where there may be multiple physical cores ,each with multiple strands.Each virtual processor has its own interrupt ID. At any given time , an operating system can have a different thread scheduled on each virtual processor.
We very much appreciate postings like this, pointing out ambiguities in the architecture specification!
Mr. Sankarshanan's posting suggests a modification of the definition from the UltraSPARC Architecture 2005 document (downloadable from page http://opensparc.sunsource.net/nonav/opensparct1.html).This modification points out an ambiguity in the original definition, as to the meaning of "corresponds to" in this context.In the original definition, "corresponds to" was intended to imply identity (a 1-to-1 correspondence), but Mr. Sankarshanan's posting points out that it could be taken to mean membership in.
Virtual processor is software's view of a hardware strand; for all intents and purposes, those terms are synonymous.There may be multiple strands per physical core (e.g. 4, on UltraSPARC T1) and multiple physical cores per processor (e.g. 8, on UltraSPARC T1). Here's an attempt to disambiguate the definition by removing the term "corresponds to"...
VIRTUAL PROCESSOR: The term virtual processor, or virtual processor core, is used to identify each strand in a processor. A processor contains one or more physical cores, each of which contains one or more virtual processors (strands). Each virtual processor has its own interrupt ID. At any given time, an operating system can have a different thread scheduled on each virtual processor.See also pipeline, processor, strand, and thread.
Just FYI -- public postings are always welcome. If for any reason someone wants to send comments regarding a specification via email, those can be sent to the email address found inside the front cover of the relevant document (in the case of the UltraSPARC Architecture, it's UA-editor@sun.com ).
= David Weaver(Editor, UltraSPARC Architecture 2005)
