[lug] sluggish machine

[Davide Del Vento]

Folks,
I'm having a weird problem. My laptop is slowing down often, up to a
point where it becomes unusable. Then it return faster as it was, or
sometimes (like when I wrote the first draft of this email) still very
slow, but usable - I am typing about two words forward the ones it is
showing on the screen.

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The facts:
The machine becomes incredibly slow, system monitor reports 100% CPU
usage, and many windows (most notably firefox) become irresponsive and
grayed-out.

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The clues:
System monitor (as well as top) does not report a single process that
is hogging all the resources, but it might not able to refresh often
enough. The top-six for memory and CPU are firefox, xorg, evolution,
thunderbird, system monitor itself and (oddly?) geyes. The rest are in
the single digit (or even 0.something) range.

The obvious suspects are javascript in the large number of pages I
keep active in firefox (I need them, don't suggest to not use them,
they are almost all work related, besides gmail for chatting with
family and friends - maybe chrome would have been better to pinpoint
the guilty site, but we don't have it for linux)
On a similar system (older hw, same OS, maybe slightly different
packets installed - oddly less carefully picked, like skype) they the
same websites don't create this mess! So it's not (entirely) web's
fault.

I did deleted my .mozilla directory and let firefox re-create it
again. Painful (autocompletion, history, settings lost, etc) and
useless: the problem si exactly the same. I unistalled  firebug (but
it was disabled...), I uninstalled completely firefox-3.0 and all
related packages (gnome-support, ubufox, etc), did apt-get autoclean
and autoremove. After reinstalling (firebug excluded) the problem is
still here (less frequent, maybe...)

RootKit might be a possibility, but nmap didn't find anything, and
rkhunter, unhide and chkrootkit didn't find anything "too strange"
(well, it did find something, but many people online say that are
false positive - or are they the RootKit authors? - and then a true
positive might hide in the list). And I trust more nmap than
rkhunter, unhide and chkrootkit.

Fragmentation may contribute to the issue, since everything started
when I had to create a couple of multi-gigabyte files (suddenly
raising my / usage from ~30% to ~70%) and I had to read these files
with my own python scripts to do some data-analysis. During that time
the system was REALLY sluggish and started to swap, but at the end the
process was successful. But fragmentation does not explain the 100%
CPU usage (which files should I check with filefrag -v?)

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The system:
Ubuntu Hardy 8.04.2 - fully kept updated
Linux-2.6.24-24-generic  i686
Gnome 2.22.3

Dell Dual Core U7600 @ 1.2GHz
2GiB RAM

Usually used with Dell dock-station and external keyboard, mouse and monitor.

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Do you have any suggestion? Even if not, thanks for reading this long message.

Bye,
;Dav