<p>Recently I have been having issues with Firefox 3 on Ubuntu Hardy Heron.</p>

<p>I will click on a link and it will hang for a while.  I don't know if its a bug in Firefox 3 or a page running too much client side JavaScript, but I would like to try and debug it a bit.</p>

<p>So, my question is "is there a way to have some kind of process explorer, or task manager sort of thing for Firefox 3?"</p>

<p>I would like to be able to see what tabs are using what percent of my processor via the JavaScript on that page (or anything in the page that is causing CPU/memory usage).  </p>

<p>Does anybody know of a plugin that does this, or something similar?  Has anyone else done this kind of inspection another way?</p>

<p>I know about FireBug, but I can't imagine how I would use it to finger which tab is using a lot of resources.</p>

<p>Any suggestions or insights?</p>

It's probably the
awesome firefox3 fsync "bug"
, which is a giant pile of fail.
In summary
Firefox3 saves its bookmarks and history in an SQLite database
Every time you load a page it writes to this database several times
SQLite cares deeply that you don't lose your bookmarks, so each time it writes, instructs the kernel to flush it's database file to disk and ensure that it's fully written
Many variants of linux, when told to flush like that, flush EVERY FILE. This may take up to a minute or more if you have background tasks doing any kind of disk intensive stuff.
The kernel makes firefox wait while this flush happens, which locks up the UI.