Now that Bug 625302 has landed, it should be possible to add a "CC" button to about memory that runs the cycle collector without (necessarily) running the GC. This is mostly a fiddly option that won't matter much, but it could be handy. Another thing to consider would be to add a button to do a CC that does a heap dump, as outlined here: https://wiki.mozilla.org/Performance:Leak_Tools#Cycle_collector_heap_dump I don't know if I am totally comfortable with a button that you click that dumps out a file, but the capability is already there to some extent.

Oh, and this could replace the GC+CC button that currently exists.

completely untested

Oops, forgot to update the description and remove the comment about why we don't have a pure CC button.

changed the name of the function called to doGC(), instead of doGlobalCC(). I tested this a little. I used javascript.options.mem.log to confirm that clicking on the CC button causes a CC and no GC.

Try run for 4432748009fe is complete. Detailed breakdown of the results available here: http://tbpl.mozilla.org/?tree=Try&rev=4432748009fe Results (out of 170 total builds): success: 153 warnings: 15 failure: 2 Builds available at http://ftp.mozilla.org/pub/mozilla.org/firefox/try-builds/amccreight@mozilla.com-4432748009fe