Newsgroups: comp.parallel,comp.sys.intel
From: campbell@minster.york.ac.uk (Duncan Campbell)
Subject: Re: Context-switching on the Intel i860XP
Organization: Acadia University
Date: Sun, 5 Feb 1995 01:23:20 GMT
Message-ID: <1995Jan31.123248.28794@leeds.ac.uk>

D Lamptey (D.Lamptey@sheffield.ac.uk) wrote:
: campbell@minster.york.ac.uk wrote:
: : Has anyone out there written a context-switching package for the Intel
: : i860XP, as used on the Paramid parallel computer?
: : If so, could you please let me have the details.

: ... meaning, it is not used in the Paramid? Because that's how I understood
: it.

Right.  The Paramid uses i860s and only allows one process per
processor, but we want to use more than one process per processor
on it.

: It'll be hard to see how one can make a great context-switch out
: of the i860, as I seem to remember the Csw being around 70 microsecs.

We're not exactly concerned about the performance aspect of the
context-switch of an i860 for this research, we just want to be able
to do it, and if someone else has done it and can tell us about it, that
would save use wasting a lot of effort.

: And I understood it was a h/w limitation rather than anything else...

...basically the flushing and refilling of the visible pipes in the
Floating Point Unit.

: What does the iPSC, and the other i860 based machines do?

Can someone tell?

--
Duncan Campbell              *************    I am a novelist, honest. 
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