[mythtv-users] High load, low CPU usage

Steve Hill steve at nexusuk.org
Fri Jul 11 20:45:25 EDT 2003


I am recording MPEG4 at 416x576, 2200Kbps and audio quality 7, 32000KHz.  
The hardware is an Athlon XP 2100+ with a WinTV/PCI bt848 tv card.
The frontend and backend run on the same machine.

While recording, the backend's CPU usage varies between about 15% and 
40% with the load average usually below 0.50.

When playing the frontend uses under 5% CPU and the load average is under 
0.02.

The problems start when I am playing at the same time (e.g. LiveTV) - The 
load average varies anywhere from 0.50 to over 3.00.  This results in 
choppy video, and loss of AV sync.  The front end also sometimes reports 
audio buffer overflows.

DMA mode is turned on on the hard drive, although it isn't hitting the 
disk much anyway.

Does anyone have any ideas what might be causing the problem?  I can't 
understand why it works fine recording and playing separately but 
recording and playing symultaneously causes such a lot of load, especially 
since there is plenty of free CPU time.

-- 

 - Steve                                             http://www.nexusuk.org/

"..Learning that we're only immortal for a limited time.." - Dreamline, Rush
        *** Presented in DoubleVision (Where Drunk) - Futurama ***




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