[mythtv] performance

Ray mythtv-dev@snowman.net
Fri, 13 Dec 2002 17:28:04 -0700

On Fri, Dec 13, 2002 at 03:20:52PM -0800, Chuck Ferring wrote:
> I noticed that watching live TV uses 95-100% CPU time using mpeg4
> encoding at 640 X 480.  My system is an Athlon XP 1800 with 256M PC 2100
> ram.  Running hdparm tells me that my hard drive throughput is about 23
> Mb / sec.  Is this performance about what I should expect?  If so, what
> would be the best way to increase performance, more memory, faster
> processor or faster hard drive?

It's really sort of odd, some people with similar systems seem to be
performing MUCH better but there are number of people with performance much
like yours.  For some of these people it turns out to be that dma either is
not enabled or is not being fully taken advantage of (no 80 wire cable,
wrong ide driver in kernel etc) but there also seem to be a number of
"mystry systems" on this list that just arn't performing as well as they
should.  Hopefully one of the people with problems will start collecting as
much info as they can from everyone who is having problems (after
eliminating the DMA issue) and start looking for patterns.  It would also
help to collect data on the cpu usage during JUST record and JUST playback
and compare with similar systems that seem to be working correctly.  It
could be a particular sound card/sound driver, video card/driver,
motherboard chipset etc is basically hogging the machine while it waits for
some event to happen.  It also could be that with some distros Myth (or
really avilib) isn't using whatever optomizations are available for a
particular cpu.  I know on my system it seems that just about every
player/encoder needs it's own different version of avilib for example.