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From: cutting@parc.xerox.com (Doug Cutting)
Newsgroups: comp.lang.lisp
Subject: Re: effects of rumored 16 meg virtual memory threshhold on Sparc lisps
Message-ID: <CUTTING.90Jul24172214@elsinore.parc.xerox.com>
Date: 25 Jul 90 00:22:14 GMT
References: <14613@csli.Stanford.EDU>
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Organization: Xerox PARC, Palo Alto, CA
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In-reply-to: lakin@csli.Stanford.EDU's message of 24 Jul 90 17:26:28 GMT

In article <14613@csli.Stanford.EDU> lakin@csli.Stanford.EDU writes:

   I'm curious as to responses from users,vendors, proponents and lisp
   others to this depressing note on sun-spots recently:

     Date:    9 Jul 90 00:09:14 GMT
     From:    gordoni@chook.ua.oz.au (Gordon Irlam)
     Subject: Sun-4 MMU Performance

     Throughput on a Sparcstation drops substantially once the amount of active
     virtual memory exceeds 16M, and by the time it reaches 25M the machine can
     be running up to 10 times slower than normal.  This is the conclusion I
     reach from running a simplistic test program on an otherwise idle
     Sparcstation.

We two have been bitten by this, but have been informed that Sun will
have a patch for this out quite soon (in a few weeks, according to our
unofficial source).  For ~25Mb Lisp jobs I've experienced a slowdown
closer to 2x, but performance will vary with locality of reference.

	Doug