Firefox slows down pc......

[Marcel J.E. Mol]

On Wed, Mar 30, 2005 at 07:22:10AM +0200, Antonio Vargas wrote:
> On Tue, 29 Mar 2005 10:32:29 +0200, Marcel J.E. Mol <marcel at mesa.nl> wrote:
> > On Tue, Mar 29, 2005 at 10:27:32AM +0200, Marcel J.E. Mol wrote:
> > > On Sun, Mar 27, 2005 at 07:46:07PM +0300, Kaspars wrote:
> > > >
> > > >  Hi,
> > > >
> > > >  I search and don`t see that there is topic about my problem yet and
> > > > don`t know is this here...
> > > >  I`m using fresh FC3 reinstalled for week and updated, problem is that
> > > > something like to eat my pc power and I found that it is firefox... New
> > > > firefox when opened couple tabs (last 5) and all try to download some
> > > > site was fulling my memory/processor, top of the "top":
> > > > 19.0 10.1   2:10.66 firefox-bin
> > > > 10.2 50.3  11:52.26 X
> > > > and load start to fullfill: load average: 5.31, 3.43, 1.98
> > > >
> > > > Last time load was go so high that something kill some process and pc
> > > > freeze. Only reboot help...
> > > > So I`m thinking what to do, I have all updated etc. Start to think to
> > > > compile maybe by my self ff. Don`t know what to do...
> > > > Pc is year old Toshiba Satellite with p4 and 256ram.
> > >
> > >
> > > Attached is a testcase that shows high cpu usage for both firefox and mozilla.
> > > It contains a few animated gifs. I resize my browser so the bottom part of the
> > > page, including the animated gif in it, is outside the window. There are still
> > > 4 instances of the same gif visable.  CPU usage in this case is just a few %.
> > >
> > > Now when I scroll the bottom part into view so that the 5th instance of the gif
> > > becomes visible, cpu usage rises to 30% or 40%!
> > >
> > > If other people can reproduce this I can file a bugzilla...
> > 
> > I see this effect in mozilla and firefox, but not in konqueror.
> > 
> > -Marcel
> 
> this is cpu cache effects: 4 gifs at XxY rendered resolution fit ok in
> data caches but 5th one spills. perhaps konqueror uses less mem and
> thus it can fit 5 and not 6, or it already does not fit 4 and it then
> feels equally slow with 4 and 5.

That could explain it perhaps. When I remove the gifs from the top part 
one by one the extra cpu usage when getting the bottom part in view is getting
less.
But opening mozilla and konquere at the same time, konqueror showing all gifs and
mozilla with the bottom part hidden show no extra cpu usage. Again moving the
bottom part in view in mozilla (so I see all animations in both mozilla and
konqueror at the same time) gives a sudden increase in cpu usage.

I also created simple html page with increasing numbers of this animated gif and
even with 20 of them in view cpu usages stays practically 0%!

I think there must be something more...

-Marcel