121721 - CPU usage high on CFM builds

Status: RESOLVED INVALID

(SeaMonkey :: General, enhancement)

Description

[Louis Wang]

CFM builds of mozilla under OS X will regularly spike to 60%-70% CPU usage while
idle.

I've noticed this as far back as 11-2001, when I started playing with Mozilla
(and running OS X regularly).

This is in comparison with the macho builds, which will spike to 7% or so.

Low water mark for CFM: 4.8%
Low water mark for macho: 1.9%
High water mark for CFM: ~70%
High water mark for macho: 3.9%
Average CFM: 9.7%
Average macho: 2.8%

These numbers are highly subjective, as I just let top run for a few moments
(top -du in Terminal.app) to see what kind of difference existed between the two
apps.

I know that the macho build leverages a lot of Unix specific code, or something
to the sort, while the CFM build uses the more native Carbon API. Perhaps it's
impossible for Carbon code to approach native Unix or native Cocoa code, but is
it impossible to prevent the CFM code from throttling it's own performance by
sucking up over 50% of the CPU while idle? It gets worse when it isn't idle.

In non idle mode, the macho build will run to about 40% while scrolling and
other stuff, while the CFM build will rise up to 80%.

Anyway, it means that, on a laptop, Mozilla-CFM in idle will suck up more
resources and generally slow down the whole machine in general. This may be more
of an enhancement request, as CFM does work, but does not work well? It's hard
not to tell people to use the macho build when it sucks up so much less CPU than
CFM, except for bugs that make keyboard accelerators break, downloading files
break, NSS isn't ported, and plugins don't work. Is it too much to hope that
macho becomes standard and CFM allowed to fall to the wayside?

Comment 1

[Asa Dotzler [:asa]]

this kind of information probably belongs in the performance newsgroup.