User Agent: Mozilla/5.0 (X11; Linux x86_64; rv:38.0) Gecko/20100101 Firefox/38.0 Build ID: 20150120030203 Steps to reproduce: Dunno. It just happens a lot lately. Expected results: "A web page" is really not very useful with 500+ tabs over 12 windows open. Please make this message, and any others more specific, so that we have a chance to find the culprit.

Um.... THAT is the message I, the user, gets... The complete message disappears too fast to get the entire exact text; but I think it continues with: "What do you want to do about it? [ Options ]" Even if the message, which appears at the top of the current page, stayed up longer so that I could grab the mouse and click "Options"; I'm not convinced that there would be much more info to go on... and _this_ is my point about messages which are too generic to be of any use. There are other performance problems I'm trying to get a handle on; but I've been searching for a FF profiler -- unsuccessful so far. At least this message is useless enough to ask for more info from FF; which is what this issue is about... HTH

> FF profiler exploring within FF; found the Performance tab -- will try that...

The options listed are: stop script, debug script, and kill web process.

Moot since the message and Options button don't sick around long enough to grab the mouse, aim it and click... :] Is the timer value in about:config? Didn't find anything obvious.

oops, sorry.

(In reply to Pierre Fortin from comment #1) > messages which are too generic to be of any use. There are other > performance problems I'm trying to get a handle on; but I've been searching > for a FF profiler -- unsuccessful so far. > This perhaps https://developer.mozilla.org/en-US/docs/Mozilla/Performance/Profiling_with_the_Built-in_Profiler ?

(In reply to alex_mayorga from comment #7) > This perhaps > https://developer.mozilla.org/en-US/docs/Mozilla/Performance/ > Profiling_with_the_Built-in_Profiler ? Thanks Alex, but... Actually, many of the thus-far-unreportable problems I'm experiencing cause FF to hang/stall for many seconds, making built-in profilers useless. Switching FF windows just gives blank window until the problem clears itself. So I'm looking for something external like gdb|strace|? wrapped with a display of counters showing where FF is spending its time (in order of implementation priority): windows, tabs, sites, scripts, network, ... Like top, htop, iotop, etc.; but focused on an application's footprint -- functions/subroutines, libs, etc -- not necessarily specific to FF. In the early days of browsers on wimpy hardware, not a big deal; but I now run FF with 9-12 windows handling 500+ tabs that I move between quite a bit. And no, FF is not acting up because of the load I apply to it -- I see CPU activity either going quite high with no apparent reason, or going to near zero indicating FF has hit a blocking waitfor() of some sort At my age, I hate to waste time re-doing previous "search for, find, load, etc", only to get lost in those details and forget why I was going there in the first place... especially when I've already gone through all those steps once -- call it one_time_brain_init() :) And why I really appreciate session restore. FF often realizes something abnormal is happening and informs the user in various ways; but, if FF could be more specific than, for example, "a script...", I could dig in and be able to provide more specific bug reports. At the moment, I experience loop/hang/stall issues for which there is ZERO clue, so I can only resort to mental pattern matching in the hopes of an eventual "Ah-ha!" moment.

Should add: My recent bug 1120621 was only discovered by accident because I have gkrellm running to the side of FF watching my 4-core(8 thread) CPU with 32GB of memory (recently upgraded from 16GB because swapping was masking real stall/hang issues). The built-in profiler is similar to gkrellm; except that there should be an external version...