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Re: Fedora-10 nightmare update2

Arne Chr. Jorgensen wrote, On 04/17/2009 03:02 PM:

I did describe noise/glitches on the screen.

I will try to describe it a little bit: ---------------------------------------

It is like an old CRT with a weak
high voltage supply - the screen may shrink or expand. And there are noise
streaks across the screen.

As this is a laptop with LCD, it has to do with updating of the screen. Loading is typical if you open a folder on the screen, and it will update/paint to the screen. In such cases the shrinking/expansion may be
20-40 mm for a brief half second or so. Sometimes leaving a horizontal band
for in the middle. The reason:

The "new" cpu scaling can not keep up. I have it set to "on-demand".
 800MHz - worst, as described above.
1600MHz - very improved, the shrinking/expanding is only 5-10 mm 1800MHz - the effect seem gone.
2000MHz - have not seen any noise/glitches.


Watching the System Monitor, the graphs are smooth, the loading on CPU1 and
CPU2 seem nice compared to earlier kernels with abrupt switching from one
to the other.

To remove noise on the screen, perhaps a sharper controller term could be
used, at the cost of the more smooth behaviour it has now. Perhaps the
refresh of the screen could be held off/protected during scheduling. I don't know.
Knowing some reasons for this and if need be, just enable a higher prosessor speed, works for me.


if you do
taskset -p 0x00000002 \
 `ps aux |grep /usr/bin/Xorg| \
  grep -v grep |awk '{print $2}'`

{painful way to get the X pid to feed to taskset, which suggests to the kernel keep the X process on the second processor.}

and then run your tests, does the problem seem less troublesome at the lower speeds?

Todd Denniston
Crane Division, Naval Surface Warfare Center (NSWC Crane)
Harnessing the Power of Technology for the Warfighter

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