Xorg CPU usage question

[David L]

On Tue, Oct 6, 2009 at 10:27 AM, Adam Jackson wrote:
> On Tue, 2009-10-06 at 08:03 -0700, David L wrote:
>> I don't think think this is specific to rawhide, but it seems
>> maybe a bit worse in rawhide, so I'm asking on this list.
>> I have a gnome terminal running an app that prints a lot
>> of lines (perhaps 60 100 character lines per second).
>> This causes Xorg to use about 50% of my CPU as
>> reported by top, and X responsiveness is really bad.
>>
>> I'm running the vesa driver due to this problem:
>> https://bugzilla.redhat.com/show_bug.cgi?id=504048
>>
>> So maybe not running a driver optimized for my hardware
>> is part of the problem.
>
> Yes, it's almost all of the problem in fact.

Well, I just tried the intel driver using up to date rawhide
and the problem is even worse (60% CPU usage to
scroll 60 lines per sec... that's 28 million CPU clock cycles
per line printed).  If I reduce the window size to one line, the
CPU load goes down to about 30%, or 14 million clock
cycles per line or ~140,000 clock cycles per character
printed.  Something ain't right.

This was with no xorg.conf which uses the intel driver with
default settings I guess.

Cheers...

              David