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p7zip 9.20.1b "testing" (Users)

posted by Zyzzle, 26.08.2012, 04:09

> > If you've got the time, it would be interesting to test how the size and
> > speed with -Os compares.
>
> http://ftp.ibiblio.org/pub/micro/pc-stuff/freedos/files/util/file/7zip/9.20.1/p7z9201b-misc.zip
> (2.1 MB)
>
>
> Archive:  p7z9201b-misc.zip
> Zip file size: 2206984 bytes, number of entries: 5
> -rwxa--     6.3 fat   195244 b- defN 12-Aug-24 18:26 7zcon.exe
> -rwxa--     6.3 fat   553556 b- defN 12-Aug-24 18:24 o3-i686.exe
> -rwxa--     6.3 fat   600620 b- defN 12-Aug-24 18:24 o3i486fp.exe
> -rwxa--     6.3 fat   414704 b- defN 12-Aug-24 18:24 os-i386.exe
> -rwxa--     6.3 fat   451168 b- defN 12-Aug-24 18:24 osi486fp.exe
> 5 files, 2215292 bytes uncompressed, 2206472 bytes compressed:  0.4%
>
>
> N.B. Since I was recompiling anyways, I figured I'd also do the "obvious"
> and make a "small as possible" sfx module. (Why didn't I think of that
> before?) Still too big, honestly, but whatever, I guess it supports lots of
> things that 7zdecode doesn't.
The completely surprising result is that of all those misc versions, the osi486fp.exe works best and fastest on my Atom netbook. it is quite a bit faster than any other version of 7zip posted on this forum so far, by around 3% compression and 10-15% in decompression. Also, that version DOES work fine with .exe filters and -mx8 and -mx9. For my i7, this optimized for size i486 version actually compresses 0.5 to 1% faster than your other versions, and decompresses faster, around 5%. Of course decompression speed of your optimized 7zdec.exe 9.12 beats all these versions by around 50% on my netbook (yes, it decompresses the same archive in 14 sec that osi486fp.exe decompresses in 28 seconds, and o3i686.exe take 33 seconds to extract. This is just one archive, others have tested the same.

Deflate is also improved most by osi486fp.exe in -mx9 mode around 3-5% and in other modes around 7-10%! Wonder why?? This on both my systems. I'll also test on a Core2Duo E8400 chip...

As expected, os-i386.exe is slowest by around 15% on both my systems.

> FYI, these "misc" binaries mentioned in this post did not workaround such a
> thing, so they probably still have that bug. Sorry, but I didn't want to
> complicate (or confuse) any benchmarking. If you really want, I can
> recompile again with same switches and have them all "fixed" (just use
> "-Os" for the BCJ*.cpp files). But honestly, I think random benchmarking
> non-.EXE files should be sufficient for now.
But in my testing osi486.exe works perfectly on all settings, and o3-i686.exe fails on mx8 and -mx9 and exe filters. Very strange.

> It's an interesting idea to compile for various machines, but if it doesn't
> show much benefit, there isn't much point. So I'd rather target only one or
> two common ones, if possible (so as not to be too confusing). BUT ... we
> shall see. ;-)
There seems to be quite a spread over the different compiles of 7zip! More than just 1 or 2% that you might suspect.

Also, there was a vastly increased speed of your AdvanceZIP recompile. For -z -4 method, a typical decrease in time was from 60.4 sec using the 2005 compile to 41.7 sec using your compile. Bravo! What a great difference. This speed optimization holds for both my i7 and Atom systems. Thanks for making these compiles available. There was only around 2% difference in the generic and i686 and Atom versions, however. Times for that same archive ranged from 41.7 sec (fastest = generic) to 42.5 sec (slowest = i686). Wonder why with 7zip there is more variance.

By the way, all my tests were done on a RAMdrive to minimize variation in HD speed affecting the results.

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