[mythtv-users] What is a normal X CPU usage?

Henk Poley hpoley at dds.nl
Thu Feb 26 03:49:29 EST 2004


> Van: Niklas Brunlid <nbr at ticalc.org>
> 
> I've read what I've found in the archives (not that "X" is that
> easy to search for) but I'm still wondering; what is a "normal" CPU
> usage level for X? My mythbox is a Pundit running in mirror mode at
> 720x576 using the 2/19 drivers from Winischofer, and on my 2.4GHz
> P4 I get an X usage of 5-9%. A lot of people seem to get as low
> as <1%...

Yes, finaly someone else with the same 'problem'. I've already mailed
Thomas Winischhofer, and he has no idea. The guy who reported the < 1%
usage seems to be pretty sure that he is correct. The only time I see that
is when I switch to a 'flat' console (kernel framebuffer) then X will
discard all Xv frames or something.

I think I've got all the 'gizmos' (MTRR on, P4 optimized, BIOS set to
speculative write for video mem) needed for fast graphics card memory
access switched on. I run my Pundit with a Celeron 2.4GHz, Gentoo, Xfree86
4.3.0-1 (AFAIK), sis_drv.o 2/19.2004, sisfb 2/19, kernel 2.6.3, 512MB RAM,
of which 64MB is shared video mem.

It might be that 640x480 is easier for the card or something. I (also) run
in 720x576 so DVDs and PAL TV looks better.

The wierd thing is X uses much less CPU (about half) when I use mplayer or
Ogle, no matter what 'wierd' video (not X) resolution I throw at it. So
there at least is something 'different' in MythTV.

> Are there any Pundit users who go this low? What's the secret
> XF86Confif? I've checked for NoAccel and XvOnCRT2. Do I need to
> run in MergedFB or Xinerama mode to make xv-acceleration kick in?

I haven't tried Xinerama nor MergedFB, I don't need it. Both are for
'glueing' 2 screens together. AFAIK: In Xinerama mode you have two
independant screens which can be moved around the X framebuffer. In
MergedFB you have 'one' screen in which one half will be displayed on CRT1
and the other half on CRT2.

>From what I've read it's easier to implement on-the-fly Xv-acceleration
screen switching (aka move video playback to the other CRT) with MergedFB,
since X will only see one screen and the driver implements the Xv
acceleration.

	Henk Poley <><


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