[mythtv] MythVideo unberably slow in high resolution, 100% cpu usage by X11.

Mikael Leiviskä lereg at zero-kelvin.org
Wed Oct 17 23:19:01 UTC 2007

Earlier I was running mythtv on my media box ( AMD XP2500+ Barton OC'd
to 200x10, 1024mb ram GF4 ti4800, 3x 120gb disks in raid5) and using TV
output in 640x480 and everything was fine the menus were snappy etc, no
But I recently got a new display that has 1920x1200 as it's native
resolution and after disabling tv-out and using this new resolution
mythtv has come to it's knees crawling... When I keep top up and scroll
in the video list cpu usage goes up to 100% with 99% being eaten by X11.

I've checked the regular things, I'm running the most up to date nvidia
driver that there is for my card (it's been bumped down to legacy, those
bastards..  :)  ). And I'm using the nvidia driver, not nv. I have DMA on
my drives and I get good transfer rates on them. I can playback 720p
movies scaled using mplayer -vo gl2 no problem, so disk and cpu and
graphics is not the problem.

Also glxgears gives around 5k fps as it always has done. So I hardly
believe it's my hardware at fault here. Further more mythtv becomes more
responsive the lower I set my X11 resolution. And yes I use the GL painter.

I suspect that the problem comes from an inappropriate X11 call causing
a lot of pixels to be blitted in software for some reason. Or that there
is something strange going on with the fonts. Them being rastered in
software or the glyphs not being cached properly or something.

Any ideas? I'd try to hack it myself but I don't really have time now.
I'm building mythtv with -p now to see where the bottleneck is.
Oh and it's version 0.20.2_p14324 from gentoo portage.

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