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÷ Sun, 11 May 2014 18:26:32 -0500 |
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Gordon Pettey <petteyg359@×××××.com> ÐÉÛÅÔ: |
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> A lot of small files (e.g. AUTHORS, ChangeLog |
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> |
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> FWIW: On my system, I have 59M of bz2 files in /usr/share/man and |
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> /usr/share/doc. A short script to decompress those and recompress with xz |
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> -6e reduced that to 36M. |
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Very strange o_O |
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Here is my test results. xz options: "--lzma2=preset=6e,dict=4MiB". |
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Larger dictionary size does not improve compression ratio, I get |
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even worse results with just "-6e" or "-9e". man-bz2 is a full copy of |
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my /usr/share/man, man-xz is a recompressed one. |
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Size comparison: |
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$ du -s man-bz2/ man-xz/ |
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82032 man-bz2/ |
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82308 man-xz/ |
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Decompression speed: |
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$ time find man-bz2/ -type f -name "*.bz2" -exec bzcat '{}' > /dev/null \; |
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real 0m35.110s |
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user 0m14.509s |
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sys 0m15.227s |
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$ time find man-bz2/ -type f -name "*.bz2" -exec bzcat '{}' > /dev/null \; |
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real 0m35.407s |
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user 0m14.432s |
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sys 0m15.186s |
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$ time find man-xz/ -type f -name "*.xz" -exec xzcat '{}' > /dev/null \; |
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real 0m46.571s |
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user 0m17.077s |
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sys 0m23.906s |
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$ time find man-xz/ -type f -name "*.xz" -exec xzcat '{}' > /dev/null \; |
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real 0m46.137s |
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user 0m17.276s |
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sys 0m23.426s |
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As you can see, xz is actually worse in speed and compression ratio. |
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-- |
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Alexander Tsoy |
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