Hello, please which Linux command can help me discover which Firefox extension is eating most of the CPU?
ps and top shows firefox processes, threads but im not recognizing particular extensions out of that info.

Extensions would not normally show up in commands like top, try disabling all extensions and then add themnback one by one till you find the bad one, I'd start with flash.

There ain't no Linux command for that. Only Firefox knows, or cares, what extensions are running. To the kernel, it's all Firefox. As Keith said, disable everything, then enable extensions one at a time until you find the culprit, if it is even an extension. It might be Firefox itself, it's a known resource hog.

...and of the 724,000 hits in Google for "discover which Firefox extension is eating most of the cpu", there is much you can do. There are Firefox extensions to measure CPU and memory usage for each add-on and tab. Further, if you looked at any of the Firefox documentation, you'd have seen you could just type in "about:memory" (or "about:addons-memory") into your browser, and see detailed memory-tree usage, which will point you towards the culprit. You'd also see this has been an outstanding feature request since 2007:
https://bugzilla.mozilla.org/show_bug.cgi?id=400120

Did you try to look any of this up?

FYI "about:addons-memory" is a plugin and needs to be installed.
https://addons.mozilla.org/en-US/fir...addons-memory/
But is quite useful.

Yep...good clarification. I said "extensions", but plugin works too.

Yes, i already read about manually disabling/enabling one extension after another. Any suggestion how i can accurately meter the CPU impact so i can discover which ext. is bad (heavy CPU eater).

Watch the CPU usage with only the addon you're testing installed.

You were handed two in reply #4, along with the relevant bugzilla thread...did you not read/understand them?