How to interpret state and log files written by preload program in Linux?

Question

Preload is a program which prefetches files from the disk needed by various applications to reduce application startup time. It seems to be very popular and useful (just google preload+linux) but the documentation or man page seems to be bit sparse.

I am trying to understand the meaning of various values saved in log (/var/log/preload.log) and state (/var/lib/preload/preload.state) files written by preload, so that I can fine-tune which directories to preload or otherwise. I am attaching small section of the files from my computer below.

So, What are the values in different columns? Also one of the line in log file says 0kb available for preloading, using 0kb of it - What does this mean?

/var/log/preload.log

[Fri Jan 10 17:35:13 2014] state scanning begin
[Fri Jan 10 17:35:13 2014] state log dump requested
persistent state stats:
preload time = 11173110
num exes = 215
num bad exes = 0
num maps = 8554
runtime state stats:
num running exes = 72
[Fri Jan 10 17:35:13 2014] state log dump done
[Fri Jan 10 17:35:13 2014] state scanning end
[Fri Jan 10 17:35:13 2014] state predicting begin
ln(prob(~EXE)) =        -0.0009796222   /usr/NX/bin/nxnode
ln(prob(~EXE)) =        -0.0003984986   /usr/bin/Xvnc4
ln(prob(~EXE)) =        -0.0000742425   /usr/lib/gimp/2.0/plug-ins/file-ps
ln(prob(~EXE)) =        -0.0003784312   /usr/bin/mate-control-center
ln(prob(~EXE)) =        -0.0002042447   /usr/bin/mate-session-properties
ln(prob(~EXE)) =        -0.0024875406   /usr/bin/wine64-preloader
ln(prob(~EXE)) =        -0.0015284860   /usr/lib/apt/methods/bzip2
ln(prob(~EXE)) =        -0.0015595207   /usr/bin/pluma
ln(prob(~EXE)) =        -0.0103913330   /usr/bin/gnome-screensaver
[Fri Jan 10 17:35:13 2014] 0kb available for preloading, using 0kb of it
[Fri Jan 10 17:35:13 2014] nothing to readahead
[Fri Jan 10 17:35:13 2014] state predicting end
[Fri Jan 10 17:36:28 2014] state updating begin
[Fri Jan 10 17:36:28 2014] state updating end

/var/lib/preload/preload.state

PRELOAD 0.6.4   11173710
MAP     1       10      217088  2093056 -1      file:///usr/lib/gstreamer-0.10/libgstffmpeg.so
MAP     2       351450  536576  2097152 -1      file:///usr/lib/libreoffice/program/libxstor.so
MAP     3       7335780 0       16384   -1      file:///usr/lib/totem/plugins/screensaver/libscreensaver.so
MAP     4       10      352256  8192    -1      file:///usr/lib/libnm-util.so.2.3.0
MAP     9       8786090 274432  4096    -1      file:///usr/lib/i386-linux-gnu/libibus-1.0.so.0.401.0
MAP     6       7335780 12288   4096    -1      file:///usr/lib/totem/plugins/screensaver/libscreensaver.so
MAP     7       8786090 0       24576   -1      file:///usr/lib/i386-linux-gnu/libjson.so.0.0.1
MAP     8       8786090 20480   4096    -1      file:///usr/lib/i386-linux-gnu/libjson.so.0.0.1
MAP     5       8786090 0       278528  -1      file:///usr/lib/i386-linux-gnu/libibus-1.0.so.0.401.0

PS: Please excuse lack of references/links. I tried to write a better question with more reference and few images but I did not had enough reputations to post them.

Answer 1

Without digging into the source code you're probably not going to get a good answer here. Preload has not been updated since 2009 (and was initially a Google Summer of Code project from 2005).

From a 2009 blog post I found the opinion of the blog's author is:

The beautiful thing about Preload, however, is that you can ignore these files completely; you might want to check up on the log every once and a while, just to make sure that it’s running, but Preload will happily sit in the background and stay out of your way.

My thoughts are that you should just let this one go... See also...