[mythtv-users] Performance issue

[Matt Vollmar]

nate s wrote:

>nah I don't know about that... 
>
><begin anti-celeron rant>
>
>you can comapre cache sizes and all that, but the celeron usually will
>not work as well as it's specs seem to indicate it should.  there's a
>reason that many people call it the broken processer.  your celeron
>2.4 just may perform about equally to a athlon-xp 1800, maybe less.
>
><end celeron rant>
>
>still, you should be able to do what you want on that hardware...
>
>you may as well try turning deinterlacing off completely while you're
>testing, just to rule it out as a cause
>
>have you tried the non-cvs version to see if the problem still occurs?
>
>-Nate
>
>On Mon, 11 Oct 2004 15:44:04 -0500, Robert Kulagowski <bob at smalltime.com> wrote:
>  
>
>>>I would expect a Cel 2.4 to give
>>>performance 25% better than the PIII/733 or the PIII/800 lines above.
>>>I would not expect your system to be capable of recording and viewing
>>>live tv at the same time.  I'm building my first Mythbox from my
>>>Athlon 800, but I'm using a pvr-250 (or a 350) as my base encoder to
>>>reach the performance needed.
>>>
>>>      
>>>
>>
OK, I've tested a bunch of different things and I'm still having the 
same problems (pre-buffering pause and general stuttering in video but 
not audio).  Here is what I've tested to try to narrow this down:

1)  Turn off XvMC.  Result:  No difference in CPU utilization or performance
2)  Turn on/off OpenGL sync.  Result:  No difference, other than quality 
seems a little worse without it
3)  Turn off deinterlace altogether.  Result:  No difference in CPU or 
performance but much uglier
4)  Tried to use Alsa 1.0.5a, but it just messed up my system, so I 
re-installed 1.0.6.  Mandrake is funny like that.
5)  Tried changing the capture resolution, which did not change 
ANYTHING!!!  Not even load.  Interesting.

I'm now compiling different versions of the front/backend using 
different options so that I can immediately compare them.  Here is the 
one thing I've noticed:

Playback seems to take about 30% of the CPU, which seems normal 
according to what I've read.  But backend recording takes 70% or more.  
I've also noticed that when I start up "Watch TV", I get 3 prebuffering 
pauses, then no more.  The rest of the time, the playback is just a 
little too choppy to be watchable.  Ultimately, I'm not really concerned 
with Watching TV, but I want to be able to watch a movie while something 
else is recording.  Who knows when something might be scheduled, and I 
would rather not worry about it.

If it is Alsa, I may either just deal with it or try more thoroughly to 
fix it, but I have a feeling it is not.  I use "btaudio" to capture.  
Could that be it?

Matt