[gentoo-alt] Something is wrong with `file`

[Elias Pipping]

Hi,

I use file(1) on a regular basis and I've come across something really
strange.

I noticed running `file` on info pages takes *ages*.

What's confusing, is this: that's not the case with /usr/bin/file.

  % pwd
  /usr/share/info
  % time /usr/bin/file * > /dev/null
  0.201u 0.018s 0:00.22 95.4%     0+0k 0+0io 0pf+0w
  % time ~/Gentoo/usr/bin/file * > /dev/null
  28.371u 0.078s 0:28.56 99.5%    0+0k 0+4io 0pf+0w

That is a *HUGE* difference. I don't know why that is.

  % /usr/bin/file --version
  file-4.10
  magic file from /usr/share/file/magic
  % ~/Gentoo/usr/bin/file --version
  file-4.21
  magic file from /Users/pipping/Gentoo/usr/share/misc/file/magic

I've also compared some more filetypes:

  % pwd
  /usr/share/man/man7
  % time /usr/bin/file * > /dev/null
  0.034u 0.011s 0:00.04 100.0%    0+0k 0+0io 0pf+0w
  % time ~/Gentoo/usr/bin/file * > /dev/null
  1.423u 0.010s 0:01.44 99.3%     0+0k 0+0io 0pf+0w

  % pwd
  /usr/share/ri/1.8/system/YAML
  % time /usr/bin/file * > /dev/null
  0.024u 0.009s 0:00.03 66.6%     0+0k 0+0io 0pf+0w
  % time ~/Gentoo/usr/bin/file * > /dev/null
  0.049u 0.004s 0:00.05 80.0%     0+0k 0+0io 0pf+0w

  % pwd
  /usr/include
  % time /usr/bin/file * > /dev/null
  0.176u 0.014s 0:00.19 94.7%     0+0k 0+0io 0pf+0w
  % time ~/Gentoo/usr/bin/file * > /dev/null
  3.874u 0.026s 0:03.91 99.4%     0+0k 0+0io 0pf+0w

== what i compiled `file` with ==

  % emerge --info | egrep C\(XX\)\?FLAGS
  CFLAGS="-O3 -march=nocona -fomit-frame-pointer -pipe"
  CXXFLAGS="-O3 -march=nocona -fomit-frame-pointer -pipe"


Kind regards,

Elias

PS: I ran the above commands multiple times so that time's output
stabilized.

PPS: don't be tempted to benchmark in /usr/bin or /usr/lib, because
/usr/bin/file does a lot more work there, splitting up universal
binaries (on x86), hence the benchmarking results become useless.

PPPS: I've had a look at Apple's patches to file[1], but I couldn't find
one that explains the above behavior.

PPPPS: I'm attaching the output of
`diff -u /usr/share/file/magic ~/Gentoo/usr/share/misc/file/magic`

[1] http://www.opensource.apple.com/darwinsource/Current/file-6.2/patches/