Compcache testing on desktop systems?

[Kari Aliranta]

(I know the subject would probably suit better to the general
ubuntu-devel-list, but since Xubuntu is meant to be used with desktop
systems that would possibly benefit the most from compcache, I raise it
here. The compcache spec for Intrepid: https://wiki.ubuntu.com/Compcache )

Compcache  is activated for live-CD's in Intrepid (or so I've heard:
https://bugs.launchpad.net/ubuntu/+source/xubuntu-meta/+bug/70561 -
haven't tested personally if it actually reduces the Xubuntu live-CD
memory requirements), but judging from the
/etc/initramfs-tools/initramfs.conf- file of my installed Intrepid system,
it isn't activated by default on desktop systems - COMPCACHE_SIZE doesn't
have any value at all. I haven't noticed the subject being referenced here
in the mailing list nor in the ubuntu-devel-list (except for a single call
for live-cd testing), so a couple of questions follow:

- Has there been any testing of compcache on normal non-LTSP desktop systems?

- Is compcache module installed by default in desktop kernels and if it
is, how do you load it? (There is a compcache directory in
/lib/modules/2.6.27-7-generic/kernel/ubuntu - but I put a value to
COMPCACHE_SIZE and didn't see the included compcache.ko loaded)

- If compcache is loaded and operational, what would be best ways to
measure whether it actually increases performance on Xubuntu target
systems, ie. systems that have both low-memory and slow CPU? The compcache
developers seem to think that a 1,6 Ghz Pentium M is a "legacy system"
(see http://code.google.com/p/compcache/wiki/LTSPPerfSummary ) and get
very favorable performance numbers for compcache. (Personally, I have a
500 Mhz Pentium 3 laptop with 128MB ram, which is way more "legacy" than
that, and probably makes for a good testing fodder.)

Kari