Re: Poor X performance

On Jan 13, 2008 6:56 PM, Steven Kurylo <sk@infinitepigeons.org> wrote:
> I have two LTSP machines. The old machine is redhat 9 machine with
> some old ltsp version. The new machine is a ubntu feisty which runs
> ltsp 5.
>
> On identical thin client and server hardware, the new ltsp has much
> slower video playback.
>
> The users complain because firefox and thunderbird scroll pages in a
> jerky manner while the old machine is smooth. Dragging windows around
> is about the same speed, if I turn backing store on on the new
> machine.
>
> The best quantitative test I've found so far is running glxgears. On
> the old machine (X 4.3.99.901 (4.4.0 RC 1) the gears move and it says
> around 40fps. On the new machine the (X 7.2.0) the gears don't move
> at all, but it claims 80fps. However glx shouldn't be involved, as
> other applications should all be 2d.
>
> I've toggled glx, composite (only available on the new X), backing
> store, etc, etc.
>
> I'm not sure what else to compare. When I look at the X log for both
> machines I don't see any differences of consequence. The client video
> card is 3D Rage Pro.
>
> First can someone suggest a better quantitative test for X 2d speed?
> If I can measure something, it makes testing so much easier. Next,
> can anyone suggest some other bits to toggle?
>
> Otherwise I'm going to have to come to the conclusion that newer ltsp
> is plain old heavier weight than the older versions. That would be
> sad.
>

I'd be interested to know what xrestop and nethogs say about the two
setups. I have a hunch that font rendering might be causing part of
your problem, although obviously not all of it as it would be
unrelated to video playback.
Received on Sun Jan 13 20:37:36 2008