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Article #490

i860 performance again (was:Re: World's Most Powerful...)

#490
From: Larry Meadows
Date: Sun, 24 Jan 1993 02:53
28 lines
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In article <EIJKHOUT.93Jan23164314@cupid.cs.utk.edu> eijkhout@cupid.cs.utk.edu (Victor Eijkhout) writes:
>
>Assembly coded benchmarks, maybe. But the BLAS routines (Basic Linear
>Algebra Subroutines) exist on many machines in assembler, and
>precisely because they are 1/ standardized across all platforms
>2/ optimized for each, you can write real programs in Fortran or C,
>with a reasonable speed if you need the BLAS often enough.

This is a good idea, but as I pointed out, you will not get more than
11 or 12 mflops on daxpy if you stick to Blas-1 (unless you have some
kind of special daxpy [ maybe KAI? ] that assumes that vector 1 stays
in cache and vector 2 comes from main memory, or vice versa).

>
>Just interface your program to assembler *kernels*.
>
>I know of people who write distributed memory linear system
>solvers, that get over 50% performance out of *500 i860's*
>using those assembler BLAS.

These people must be using the Delta, huh?  I don't know anyone else
that has 500 i860s. Are they calling blas-2
routines?  If so, I'd definitely believe you, as I know people who get
90%+ performance on 80 or so shared memory i860-XRs using similar
techniques.
-- 
Larry Meadows		The Portland Group
lfm@pgroup.com
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Path: arc1-ca.pugleaf.net!sparky!uunet!pgroup!lfm
References: <1993Jan21.165159.10149@meiko.com> <1993Jan22.015827.26653@nas.nasa.gov> <EIJKHOUT.93Jan23164314@cupid.cs.utk.edu>

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Newsgroups: comp.sys.super
Path: arc1-ca.pugleaf.net!sparky!uunet!pgroup!lfm
From: lfm@pgroup.com (Larry Meadows)
Subject: i860 performance again (was:Re: World's Most Powerful...)
Message-ID: <C1C81H.A37@pgroup.com>
Date: Sun, 24 Jan 1993 02:53:41 GMT
Distribution: inet
References: <1993Jan21.165159.10149@meiko.com> <1993Jan22.015827.26653@nas.nasa.gov> <EIJKHOUT.93Jan23164314@cupid.cs.utk.edu>
Organization: The Portland Group, Portland, OR
Lines: 28