why is firefox such a CPU hog?

[David Groos]

I'd like to tell you about my felicity with localapps.  Last spring when I
finally got LTSP running and throughout the spring firefox did most of what
I asked it to do... except it couldn't do flash video and even java applets
like the ones at this famous site <http://phet.colorado.edu/simulations/>were
very pokey.  But that was pretty much OK.  But, what brought my curriculum
to it's knees was not being able to run CmapTools, a java based
application.  The server would bog down with just 1 or at max 2 computers
running CmapTools.

The development of localapps has saved the day for my class/curriculum.
Firefox and CmapTools work quite well as localapps using PIII and PIV
computers with no more than 512 MB RAM.  I can't say enough good stuff about
what they let me do.  Localapps IS the reason I upgraded to Jaunty.

I'll too help you make the move to Jaunty--I can't say number of hours on a
thing like this (alas, one never knows), but it is worth it if you need cpu
hogs as tools for your students.  If I can help let me know as well!

Good Luck
David

On Mon, Nov 16, 2009 at 2:10 PM, Scott Balneaves <sbalneav at legalaid.mb.ca>wrote:

> On Mon, Nov 16, 2009 at 11:08:37AM -0800, john wrote:
> > Hi Asmo,
> >
> > On Mon, Nov 16, 2009 at 10:36 AM,  <asmo.koskinen at arkki.info> wrote:
> >
> > > Do you know what they are doing/what kind of web pages they are surfing
> -
> > > flash, java, lots of pictures, some kind of embedded movies or embedded
> > > audio players, lots of popup windows and so on - FF has n+1 plugins -
> bad,
> > > bad dog. But maybe FF is not so bad, but bad design for web pages can
> do
> > > that.
> >
> > They are probably surfing all of the above, since that is the nature
> > of the web these days. I think If
> > LTSP is going to be viable
>
> Right, because we're only celebrating our 10th anniversary.  It's not like
> we're viable or anything :)
>
> > it has to be able to work at least as well
> > as other computers that kids use
> > e.g. 4 year old stand alone workstations, 2Ghz, running WinXP with 512
> > mb ram.
>
> Well, it certainly does.  I run about 40 people off one server.  Trick is,
> I
> don't load flash.  Now, I'm at a business, and can control this.  Flash is
> a
> "poorly" behaved application: it essentially assumes you're one person
> running
> on 1 machine.  So if you have 30 kids trying to watch flash movies, yeah,
> you
> either need a machine with 30x the power of your 2 ghz machine, or you need
> to
> spread the load around.
>
> Which is why we developed localapps.  Offload the firefox on the thin
> client.
>
> > If LTSP/Ubuntu can't manage that the students and teachers
> > don't tend
> > to be sympathetic. We are using google apps a lot these days, and it
> > would be a bad thing for the future of LTSP at our district if we
> > figured out that LTSP wasn't up to Web 2.0 or what have you.
>
> LTSP is NOT a panacea.  A thin client will never, EVER be 100% of the
> experience of a full workstation.  We've done lots of things to make LTSP
> as
> "like" a full workstation as we can, with things like Localapps, that
> allows
> you to offload some of the work on the thin client itself.  There's also
> Stephane's ltsp-cluster work which can also address this problem.
>
> However, the reality is, if you've got 30 kids each consuming 2ghz of
> processing power playing with flash stuff, then you're either going to need
> the
> equivalent of a 60ghz processor, or enough processors (say, 5 3ghz intel
> quadcores) to come up to the same processing power.
>
> Or, help out projects like Gnash which do the same thing for MUCH less cpu.
>  By
> way of a "single case" instance, here's a line out of top, with me viewing
> a
> youtube video using the adobe flash player:
>
> 2049 sbalneav  20   0  495m 120m  35m S   38  6.0   4:09.80 firefox
>
> The "38" column's important.  That's 38% cpu usage.  This is on a dual-core
> 3.0ghz workstation with 2 gigs of ram.  A not inconsiderable box.  38%,
> over a
> 1/3 busy.  So, if I hosted 2 other terminals, and THEY were watching
> youtube,
> I'd be at 100% util.
>
> Now, Here's me watching the same video, using Totem as my movie viewer:
>
> 4208 sbalneav  20   0  201m  43m  20m S    6  2.2   0:02.41 totem
>
> 6 percent.  So, if I had 15 other terminals hanging off my box, watching
> youtube videos, I'd be at 100%
>
> 3.  Versus 16.
>
> The problem here isn't LTSP.  LTSP can't "manufacture" cpu cycles out of
> thin
> air.  If a badly behaved application uses up all your cpu cycles, there's
> nothing LTSP can do about that: it's just a way of running remote X.
>
> > Thanks, I am defiantly looking around for Firefox optimization tricks,
> > although this link is about memory issues and my problem seems to be
> > CPU usage on the server. Running top on the thin clients shows me that
> > I have ram to spare.
>
> Then LocalApps may be your answer.
>
> > As I said, my question is partly a philiopical rumination e.g I am
> > really wondering why Linux/LTSP can be brought to it's knees by a
> > single user running a web-browser.
>
> Because LTSP hasn't been brought to it's knees.  The SERVER has been
> brought to
> it's knees by flash.
>
> It's just that, WITHOUT ltsp, you never SEE the box being brought to it's
> knees
> because, well, while you're watching the video, you're not doing anything
> else.
>
> Scott
>
> --
> Scott L. Balneaves | The closest you will ever come in this life to an
> Systems Department | orderly universe is a good library.
> Legal Aid Manitoba |     -- Ashleigh Brilliant
>
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