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On Mon, May 12, 2014 at 5:47 AM, Alexander Tsoy <alexander@××××.me> wrote: |
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> В Sun, 11 May 2014 18:26:32 -0500 |
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> Gordon Pettey <petteyg359@×××××.com> пишет: |
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> |
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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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> |
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> Very strange o_O |
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> |
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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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> |
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> Size comparison: |
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> |
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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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Did you skip all the files that weren't bz2 in the first place, and |
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decompress bz2 before compressing with xz? My comparison script does not |
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include uncompressed files. It copies all the bz2 files to a new folder, |
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pipes those through bzip -d to xz -6e to files in another new folder, then |
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compares the total size of those folders. Out of 8576 compressed files, |
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only 464 were larger in xz than in bz2. A very bad timing test I just did |
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showed the total decompression time of all the xz files to be half that of |
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decompressing all the bz2 files. Working on getting that data per-file and |
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averages. |
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