[SLL] limit on number of files in a directory and hashed dir vs. flat dir file access time

[Brian Hatch]

At almost 2007-11-04 10:32 -0800, Ana wrote:

> I disabled some stuff that had the greatest chance of interfering and
> and ran the million file test three times.  The first run took a long
> time but the second two were more in line with the lower file count
> tests.  I wonder if the first run of the test caused the file system to
> be cached which allowed the second two to run quickly?
> 
> Maybe what I need to do is boot into single user mode in order to load
> as little as possible.


To have an apples-to-apples test, you need to

  * boot into single user mode
  * run test A
  * reboot into single user mode
  * run test B
  * reboot into single user mode
  * run test C
  ...

This way each run has absolutely no kernel cache to work with, a
clean footprint at the beginning of each test, and no possibility
of extraneous processes.

(Make sure your single user mode doesn't include any network
setup - some distros do configure eth0/eth1/etc, and in theory
they could be affected by seeing and handling packets on the NIC,
such as broadcasts, DHCP renegotiation, etc.)


-- 
Brian Hatch                  Avoid the Gates of Hell.
   Systems and               Use Linux.
   Security Engineer
http://www.ifokr.org/bri/

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