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From: DCP@QUABBIN.SCRC.SYMBOLICS.COM (David C. Plummer)
Newsgroups: comp.protocols.tcp-ip
Subject: Re: TCP performance limitations
Message-ID: <871006093545.3.DCP@KOYAANISQATSI.S4CC.Symbolics.COM>
Date: Tue, 6-Oct-87 09:35:00 EDT
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Posted: Tue Oct  6 09:35:00 1987
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    Date:         Mon, 5 Oct 1987 11:24:26 EDT
    From:         Mark Bodenstein <MAB%CORNELLC.BITNET@wiscvm.wisc.edu>

    Could you provide more detail on how you unrolled this loop?

    (The complication being that the length of the loop is determined by
    the length of the data.  Some alternatives I can think of would be:

	...

There is a fourth way that we (Symbolics) have done which you did not
mentioned:

(a) Pick a compile-time unrolling factor, usually a power of 2, say 16 = 2^4.
(b) Divide the data length by the unrolling factor, obtaining a quotient
    and remainder.  When the unrolling factor is a power of two, the
    quotient is a shift and the remainder is a logical AND.
(c) Write a unrolled loop whose length is the unrolling factor.  Execute
    this loop <quotient> times.
(d) Write an un-unrolled loop (whose length is therefore 1).  Execute
    this loop <remainder> times.