Files caching analysis tool based on mincore call

Usage : fincore mode [ ARGS ] ...

 Options for trace
   -f path    Path to file for tracing
   -c count   How many snaps make
   -d gran    Time granulation, secs
   -r float   Refresh changes threshold
   -s sampl   Minimal samples bands

 Options for evict
   -f path    Path to file for evicting

 Options for stats
   -f path    Path to directory for stats
   -i         Read path names from stdin
   -d depth   Depth detalization limit
   -z         Show entries with zero usage
   -r kind    Type of reduction: none, top
   -l items   Items limit for reduction
   -s         Collect root summary stats
   -c raito   Cache filter raito for aggr


Trace mode shows short map of cached pages for a single file

$ fincore -c 1000 -d 1 -r 0.1 -f path_to_some_file

2014-08-11 00:08:39  1% [0.~.~.......~~0~.~~01000~~.0.~1~~..~.~.~~..~~~~~]
2014-08-11 00:10:59  0% [................................................]
2014-08-11 00:11:27  0% [~.~.~.......~~~~.~~~0~~~~~.~..~~0~.....~.......~]
2014-08-11 00:11:33  0% [0.~.~.......~~~~.~~000~0~~.0..0~0~.....~.......~]
2014-08-11 00:11:38  0% [0.~.~.......~~~~.~~000~0~~.0..0~0~.....~.......~]
2014-08-11 00:11:42  1% [0.~.~.......~~~~.~~01000~~.0..1~0~.....~.......~]
2014-08-11 00:11:48  1% [0.~.~.......~~~~.~~01000~~.0..1~0~.....~.......~]
2014-08-11 00:11:59  1% [0.~.~.......~~0~.~~01000~~.0..1~0~.....~.......~]

Symbols region description:
    .   uncached data
    ,   less than 0.1 % pages cached
    ~   less than 1.0 % pages cached
    0   [1, 10) percents cached
    1   [10, 20) percents cached
    ...
    9   [90, 100) percents cached
    +   all data are cached

Stats mode collects cache stats for a set of files

$ fincore stats -f /some/path -s -r top

12.9M of 7.13G  0 :summary
2.92M of 2.92M  1 3c8a037070de926448386d913a2e3378.data
2.88M of 2.88M  1 3cd103de036c9a27b8d7d9282d62db33.data
2.32M of 2.32M  1 41db756a5ec691208e74f8df7e9c0105.data
1.42M of 2.84M  1 41263a98007e62935374404b853038b6.data
1.08M of 1.17M  1 417705273a87a37a2660e3f0b51ad4c1.data
901.K of 901.K  1 3c4a7ba4036202012fd68837bd6a16f9.data
888.K of 888.K  1 3d986c2e6ddc385c3490d8bcb58a8e71.data
561.K of 561.K  1 3db207a4b42e14850253858112fb9100.data
376.K of 507.K  1 40927de25a51a4097f746a78c930c659.data
339.K of 339.K  1 3d3428ed80ab70b749b0b117a067e57a.data