Re: Vector vs Cache/Superscalar

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Article #10629

#10629

From: Rowan Hughes
Date: Mon, 06 May 1991 03:53

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>raymond> (b) Tridiagonal solving.  Comes up in lots of codes, and it is
>raymond> a real vector-breaker.  In fact, vector machines choke on all
>raymond> sorts of recursion, whereas the superscalars just love them.
>raymond> On the RS/6000, the tridiag code basically vanished, whereas on
>raymond> the vector Stardent, it was a bottleneck.

The latest Fujitsu compiler (for the VP2000 series) will handle 1st order
backwards recurrence, ie A(I)=A(I-1)+B(I), as well as the usual forward
recurrence, in full vector mode. Many old scalar problems can now be
vectorized. I'd be interested to hear if Cray/ETA/Alliant etc have this
capability too.

-- 
Rowan Hughes                                James Cook University
Marine Modelling Unit                       Townsville, Australia.
Dept. Civil and Systems Engineering         csrdh@marlin.jcu.edu.au

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Path: arc1-ca.pugleaf.net!utzoo!utgpu!news-server.csri.toronto.edu!rpi!zaphod.mps.ohio-state.edu!swrinde!elroy.jpl.nasa.gov!ames!uhccux!munnari.oz.au!brolga!bunyip.cc.uq.oz.au!marlin.jcu.edu.au!csrdh
From: csrdh@marlin.jcu.edu.au (Rowan Hughes)
Newsgroups: comp.arch
Subject: Re: Vector vs Cache/Superscalar
Message-ID: <1991May6.035310.26794@marlin.jcu.edu.au>
Date: 6 May 91 03:53:10 GMT
References: <1991May4.031835.7979@midway.uchicago.edu> <MCCALPIN.91May5075614@pereland.cms.udel.edu>
Organization: James Cook University
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