System suddenly slow down, high load-avg, almost unusable

Binary package hint: firefox

Hello guys,
        I'm experiencing some really weird and important slow downs on Hardy, updated with all the current patches.

From the user point of view, the symptoms are simple: basically the system gets irresponsive and every operation takes an amount of time which is an order of magnitude higher than normale. No particular activity is being done during those issues, I usually spend my time surfing the net with FF3.

Since I'm a performance addicted guy, I made some measuerement of my system in order to identify the bottleneks. Observing the system during this weird behaviour, I've observed that there is a clear resource bottleneck, which is my HD. Device utilization gets saturated at 95-100%, load-average rise to something like 2.8 to 4 (I have a single CPU system).

Given those evidences, I took a look at the processes, in order to identify the culprit. At first I was thinking about trackerd, but after removing it the problem was still there.

So I measured my system with some SystemTap tools and iostat. Guess what I found? The culprit seems to be FF3. Suddenly the disk start acting with very high utilization, the process using the disk the most is firefox and the read/written files seems to be the Cache dir of my firefox profile.

I attach three pertinent files: a iotime output, disktop output and iostat output. During that measurement, FF3 was open with only one tab in the ubuntuforums homepage. I have not added any extension other than what Ubuntu provided.

Please let me know what do you find, this problem yelds a really bad user experience - a friend of mine wants to uninstall ubuntu for that reason, and I have to admit that it is pretty annoying.

Thanks

Description: Ubuntu 8.04
Release: 8.04

firefox:
  Installed: 3.0~b5+nobinonly-0ubuntu3
  Candidate: 3.0~b5+nobinonly-0ubuntu3
  Version table:
 *** 3.0~b5+nobinonly-0ubuntu3 0
        500 http://sm.archive.ubuntu.com hardy/main Packages
        100 /var/lib/dpkg/status