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annotate zlib/contrib/asm586/README.586 @ 51:ae3a4bfb450b

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add some files of version 4.4.3 that have been forgotten.
author kent <kent@cr.ie.u-ryukyu.ac.jp>
date Sun, 07 Feb 2010 18:27:48 +0900
parents
children
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51
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten.
kent <kent@cr.ie.u-ryukyu.ac.jp>
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1 This is a patched version of zlib modified to use
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten.
kent <kent@cr.ie.u-ryukyu.ac.jp>
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2 Pentium-optimized assembly code in the deflation algorithm. The files
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten.
kent <kent@cr.ie.u-ryukyu.ac.jp>
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3 changed/added by this patch are:
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kent <kent@cr.ie.u-ryukyu.ac.jp>
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4
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kent <kent@cr.ie.u-ryukyu.ac.jp>
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5 README.586
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kent <kent@cr.ie.u-ryukyu.ac.jp>
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6 match.S
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kent <kent@cr.ie.u-ryukyu.ac.jp>
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7
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kent <kent@cr.ie.u-ryukyu.ac.jp>
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8 The effectiveness of these modifications is a bit marginal, as the the
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten.
kent <kent@cr.ie.u-ryukyu.ac.jp>
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9 program's bottleneck seems to be mostly L1-cache contention, for which
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten.
kent <kent@cr.ie.u-ryukyu.ac.jp>
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10 there is no real way to work around without rewriting the basic
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten.
kent <kent@cr.ie.u-ryukyu.ac.jp>
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11 algorithm. The speedup on average is around 5-10% (which is generally
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kent <kent@cr.ie.u-ryukyu.ac.jp>
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12 less than the amount of variance between subsequent executions).
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kent <kent@cr.ie.u-ryukyu.ac.jp>
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13 However, when used at level 9 compression, the cache contention can
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kent <kent@cr.ie.u-ryukyu.ac.jp>
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14 drop enough for the assembly version to achieve 10-20% speedup (and
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kent <kent@cr.ie.u-ryukyu.ac.jp>
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15 sometimes more, depending on the amount of overall redundancy in the
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kent <kent@cr.ie.u-ryukyu.ac.jp>
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16 files). Even here, though, cache contention can still be the limiting
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten.
kent <kent@cr.ie.u-ryukyu.ac.jp>
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17 factor, depending on the nature of the program using the zlib library.
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kent <kent@cr.ie.u-ryukyu.ac.jp>
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18 This may also mean that better improvements will be seen on a Pentium
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kent <kent@cr.ie.u-ryukyu.ac.jp>
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19 with MMX, which suffers much less from L1-cache contention, but I have
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kent <kent@cr.ie.u-ryukyu.ac.jp>
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20 not yet verified this.
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kent <kent@cr.ie.u-ryukyu.ac.jp>
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21
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kent <kent@cr.ie.u-ryukyu.ac.jp>
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22 Note that this code has been tailored for the Pentium in particular,
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kent <kent@cr.ie.u-ryukyu.ac.jp>
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23 and will not perform well on the Pentium Pro (due to the use of a
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kent <kent@cr.ie.u-ryukyu.ac.jp>
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24 partial register in the inner loop).
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kent <kent@cr.ie.u-ryukyu.ac.jp>
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25
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kent <kent@cr.ie.u-ryukyu.ac.jp>
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26 If you are using an assembler other than GNU as, you will have to
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kent <kent@cr.ie.u-ryukyu.ac.jp>
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27 translate match.S to use your assembler's syntax. (Have fun.)
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kent <kent@cr.ie.u-ryukyu.ac.jp>
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28
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten.
kent <kent@cr.ie.u-ryukyu.ac.jp>
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29 Brian Raiter
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kent <kent@cr.ie.u-ryukyu.ac.jp>
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30 breadbox@muppetlabs.com
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kent <kent@cr.ie.u-ryukyu.ac.jp>
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31 April, 1998
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kent <kent@cr.ie.u-ryukyu.ac.jp>
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32
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kent <kent@cr.ie.u-ryukyu.ac.jp>
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33
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kent <kent@cr.ie.u-ryukyu.ac.jp>
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34 Added for zlib 1.1.3:
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kent <kent@cr.ie.u-ryukyu.ac.jp>
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35
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kent <kent@cr.ie.u-ryukyu.ac.jp>
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36 The patches come from
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kent <kent@cr.ie.u-ryukyu.ac.jp>
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37 http://www.muppetlabs.com/~breadbox/software/assembly.html
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kent <kent@cr.ie.u-ryukyu.ac.jp>
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38
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kent <kent@cr.ie.u-ryukyu.ac.jp>
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39 To compile zlib with this asm file, copy match.S to the zlib directory
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten.
kent <kent@cr.ie.u-ryukyu.ac.jp>
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40 then do:
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kent <kent@cr.ie.u-ryukyu.ac.jp>
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41
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kent <kent@cr.ie.u-ryukyu.ac.jp>
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42 CFLAGS="-O3 -DASMV" ./configure
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kent <kent@cr.ie.u-ryukyu.ac.jp>
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43 make OBJA=match.o