Scheduler: -mm vs -staircase

Scheduler: -mm vs -staircase

[J.A. Magallon]

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Hi all...

Just a comment about a weird thing I have noticed wrt scheduling in latest
kernels.

My last two tests are 2.6.7-mm2 and 2.6.7-mm2+staircase-7.4 (plus a couple
other things, like aic updated driver). I use GLMatrix as screensaver,
running with nVidia drivers (yup, tainted kernels, but both are tainted ;)).
What I have noticed:
- With standard -mm, as GLMatrix runs, the framerate drops even to something
  like a frame every couple seconds
- With staircase, it keeps running smoothly at 25fps.

Something is strange in -mm. It keeps stoling cycles to the screensaver.
Is this expected ?

TIA

--
J.A. Magallon <jamagallon()able!es>     \               Software is like sex:
werewolf!able!es                         \         It's better when it's free
Mandrakelinux release 10.1 (Cooker) for i586
Linux 2.6.7-jam5 (gcc 3.4.1 (Mandrakelinux (Cooker) 3.4.1-0.3mdk)) #1

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Re: Scheduler: -mm vs -staircase

[J.A. Magallon]

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On 06.26, J.A. Magallon wrote:
> Hi all...
> 
> Just a comment about a weird thing I have noticed wrt scheduling in latest
> kernels.
> 
> My last two tests are 2.6.7-mm2 and 2.6.7-mm2+staircase-7.4 (plus a couple
> other things, like aic updated driver). I use GLMatrix as screensaver,
> running with nVidia drivers (yup, tainted kernels, but both are tainted ;)).
> What I have noticed:
> - With standard -mm, as GLMatrix runs, the framerate drops even to something
>   like a frame every couple seconds
> - With staircase, it keeps running smoothly at 25fps.
> 
> Something is strange in -mm. It keeps stoling cycles to the screensaver.
> Is this expected ?
> 

Sorry for the noise, it also happens with -staircase.
Lets remake the question.
I start /usr/lib/xscreensaver/glmatrix -fps, and the frame rate starts at
25 fps. In 30 seconds it has dropped to 6 fps. The app is still using 
the same cpu time (about 90% of one cpu on a dual xeon box with ht).

Any ideas ?

--
J.A. Magallon <jamagallon()able!es>     \               Software is like sex:
werewolf!able!es                         \         It's better when it's free
Mandrakelinux release 10.1 (Cooker) for i586
Linux 2.6.7-jam5 (gcc 3.4.1 (Mandrakelinux (Cooker) 3.4.1-0.3mdk)) #1

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Re: Scheduler: -mm vs -staircase

[Diego Calleja García]

El Sat, 26 Jun 2004 00:56:54 +0200 "J.A. Magallon" <jamagallon@able.es> escribió:


> I start /usr/lib/xscreensaver/glmatrix -fps, and the frame rate starts at
> 25 fps. In 30 seconds it has dropped to 6 fps. The app is still using 
> the same cpu time (about 90% of one cpu on a dual xeon box with ht).

For that particular screensaver, notice that glmatrix starts drawing nothing.
30 seconds after the start there're lots of polygons so after 20 seconds
it needs more processing power. It happens exactly the same
but the difference is not so big, from 30fps to 24fps, perhaps
you didn't enabled DRI acceleration?

Re: Scheduler: -mm vs -staircase

[Diego Calleja García]

El Sat, 26 Jun 2004 01:26:20 +0200 Diego Calleja García <diegocg@teleline.es> escribió:

> it needs more processing power. It happens exactly the same
							      ^^^^
This sentence needs a "here" to make some sense. Sorry, it's late...


> but the difference is not so big, from 30fps to 24fps, perhaps
> you didn't enabled DRI acceleration?

Re: Scheduler: -mm vs -staircase

[J.A. Magallon]

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On 06.26, Diego Calleja García wrote:
> El Sat, 26 Jun 2004 00:56:54 +0200 "J.A. Magallon" <jamagallon@able.es> escribió:
> 
> 
> > I start /usr/lib/xscreensaver/glmatrix -fps, and the frame rate starts at
> > 25 fps. In 30 seconds it has dropped to 6 fps. The app is still using 
> > the same cpu time (about 90% of one cpu on a dual xeon box with ht).
> 
> For that particular screensaver, notice that glmatrix starts drawing nothing.
> 30 seconds after the start there're lots of polygons so after 20 seconds
> it needs more processing power. It happens exactly the same
> but the difference is not so big, from 30fps to 24fps, perhaps
> you didn't enabled DRI acceleration?

This is very strange.
As I was logged in, gears gave aout 60 fps, and glmatrix degraded over time.
I have logged out and in, and gears is back to its 750 fps (GeForce FX 5200)
and glmatrix runs fine at a constant 30 fps rate (2.6.7-mm2+staircase).

raro, raro...

--
J.A. Magallon <jamagallon()able!es>     \               Software is like sex:
werewolf!able!es                         \         It's better when it's free
Mandrakelinux release 10.1 (Cooker) for i586
Linux 2.6.7-jam5 (gcc 3.4.1 (Mandrakelinux (Cooker) 3.4.1-0.3mdk)) #1

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