USing spacetrace I noticed that on startup on windows, nsExternalHelperAppService scans the list of every file extension in every mime type. I think its reading in mime types from the system. This accounted for some 300 seperate 24 byte allocations from calling nsIMIMEInfo::GetFileExtensions (well, 3 to 4 bytes really, but with alignment and malloc overhead, they're at least 24 bytes) I switched to using nsIUTF8StringEnumerator, and I managed to eliminate all of those allocations, save the 8-12 bytes for the enumerator itself. patch forthcoming.

and here's the patch, looking for reviews.

Comment on attachment 123480 [details] [diff] [review] switch to string enumerator no huge rush on these, but the patch is pretty straight forward.

Comment on attachment 123480 [details] [diff] [review] switch to string enumerator i like it! sr=darin

Comment on attachment 123480 [details] [diff] [review] switch to string enumerator r=me if you put back the |var extString = "";| that you removed in the last hunk in that diff -- that's still needed... Looks nice. ;)

fix is in!