[rescue] Mozilla Firefox
Charles Shannon Hendrix
shannon at widomaker.com
Fri Apr 23 15:55:50 CDT 2004
I'm just hijacking this thread to introduce a new on on the geeks
list. I'm posting to geeks and rescue just to kickstart it.
Please reply to geeks.
Wed, 21 Apr 2004 @ 22:12 -0400, Patrick Giagnocavo +1.717.201.3366 said:
> True. A long time ago a guy wrote a browser in TCL/TK. It ran in
> just a few MB of RAM.
I may have figured out one reason why Firefox eats so much memory. I
think it is a bug in how either it or the Linux kernel handles shared
Running pmap on the main thread, I see dozens of entries like this:
44f2e000 772K read /SYSV00000000 (deleted)
44fef000 772K read /SYSV00000000 (deleted)
450b0000 772K read /SYSV00000000 (deleted)
I assume this is shared memory mappings that are no longer used.
However, instead of the addresses being re-used, they stay in memory
map, gradually increasing VM size. Unused VM pages get swapped. Maybe
they never get swapped in again but they do take up swap, and they have
a negative effect on performance.
The total amount of these mappings is around 57MB right now. That's
57MB of unused VM that ends up eating swap space.
I assume this is shared memory used for communication between threads or
perhaps some library code. You'd have to look in the sources to know
and right now I can't endure the pain of reading Mozilla code.
This is a five-minute analysis, but anyone else have ideas? I've even
wondered if this bug is in Mozilla/Firefox, or maybe it is a Linux
I have put the full pmap output of my currently running Firefox process
I'm working on a script to track memory use of processes over the long
term to try and determine things like memory high-water marks, average
I'm thinking of writing some tools to analyze the memory maps in
Linux, but so far laziness is making a better argument than hubris or
shannon "AT" widomaker.com -- ["It's a damn poor mind that can only think
of one way to spell a word." -- Andrew Jackson]
More information about the rescue