[mythtv-users] Frontend hogs the CPU
jimc at math.ucla.edu
Tue Jul 17 05:34:39 UTC 2007
On 2007-07-14 Michael T. Dean <mtdean at thirdcontact.com> wrote:
> Don't use G.A.N.T. or any other theme that uses alphapulse; remove the
> alphapulse from the theme's base.xml; or get a modern CPU.
When I switched to the "Blue" theme, which lacks alphapulse, the CPU
load in the frontend went way down but the problem was not cured. It's
very strange: the frontend graphics respond with no delay when it's
first started, but once I watch live TV the delay starts appearing.
Here's the fix: don't use the builtin OpenGL; use Qt instead as the
paint engine. I wouldn't be surprised if Qt were using direct
rendering itself; the feature is functioning normally for other
programs. Unfortunately I don't know enough about either OpenGL or
Qt to debug the issue -- just enough to turn them on and check if
[As an aid to search engines: the symptom is that the MythTV frontend is
extremely sluggish, taking typically 20 seconds to show a visual effect
from each arrow key in the "Blue" theme and longer I think with G.A.N.T.
Some people report that the frontend is frozen; I had that impression
too, until I learned to wait a long time between keypresses. Until the
focus circle finally moves, the frontend uses 100% CPU or as much as it
can hog from other processes.]
On 2007-07-14 Robert Johnston <anaerin at gmail.com> wrote:
> First, make sure you're capturing in NUV/RTJpeg, as it's the least
> resource intensive.
> Next, drop your capture res to 480x480 (Or lower) so you don't have to
> schlump as many bytes around.
> Third, add another 256MB RAM to that box.
> Finally, make sure you have DMA enabled on your hard-drives (HDParm is
> your friend).
Thanks for the pointers. As installed, the recording profiles are all
set for RTJpeg at 480x480, and I didn't mess with any of them yet.
Compression ends up as 3.6 to 4.6 Gb/hour. Decimating to 384x384 px
is a possibility, but I hope to stick to showroom stock while in the
evaluation phase, unless resource limits truly spoil the demo.
For the memory, the real cure is to migrate to the Dell E510 which has
1 Gb RAM. But the backend and frontend do fit in the available memory
without thrashing (barely). This machine just barely has enough
resources to demonstrate that MythTV is going to handle my inputs --
but $spouse is giving it credit for doing the job.
Yes, DMA works on the disc (and the DVD reader).
James F. Carter Voice 310 825 2897 FAX 310 206 6673
UCLA-Mathnet; 6115 MSA; 405 Hilgard Ave.; Los Angeles, CA, USA 90095-1555
Email: jimc at math.ucla.edu http://www.math.ucla.edu/~jimc (q.v. for PGP key)
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