Index of /~plonka/fincore

Name	Last modified	Size

Parent Directory		-
COPYING	1996-12-17 14:59	18K
fincore	2007-05-23 16:18	8.3K
fincore_pod.html	2007-05-23 16:19	4.2K

fincore is a command that shows which pages (blocks) of a file are in core memory.
It is particularly useful for determining the contents of the buffer-cache.
The name means "File IN CORE" and I pronounce it "eff in core".

Here is some sample output:

$ fincore foo.rrd
foo.rrd: no incore pages.

$ cat foo.rrd >/dev/null # read the whole file
$ fincore foo.rrd
foo.rrd: 26 incore pages: 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25

$ ls |grep '\.rrd$' |~/perl/fincore --stdin --justsummarize
page size: 4096 bytes
2214049 pages, 8.4 Gbytes in core for 268994 files; 8.23 pages, 32.9 kbytes per file.

And the usage information:

Usage:
    fincore [options] <-stdin | file [...]>

     Options:
      -help - brief help message
      -man - full documentation
      -summary - report summary statistics for the files
      -justsummarize - just report summary statistics for the files
      -stdin - read file names from standard input

The fincore command was introduced in the paper, "Application Buffer-Cache Management for Performance: Running the World's Largest MRTG", that appears in the proceedings of the LISA 2007 conference in Dallas, November, 2007.
It is available online here:
http://www.usenix.org/events/lisa07/tech/plonka.html

You may also be interested in the related fadvise command.

Dave Plonka, May 21 2007