[mythtv] Simple player

Henk Poley mythtv-dev@snowman.net
Fri, 13 Dec 2002 10:15:17 +0100

> Van: Chris Stratton <laststraw@yahoo.com>
> I have a Athlon-xp 2100... 80GB 7200rpm 8M cache
> Here are some of my observations...
> Myth was jumpy and audio was having buffering problems according to
> console.
> I turned on DMA and I switched to ext3 for my filesystem. Don't know if
> it was the combination or one of the 2 variables...but whatever it was
> my replay is as smooth as glass now and no audio problems.
> I am recording with mpeg4 640x480 cpu runs about 54-60%

It's *probably* the DMA.

Well, DMA is a seperate 'memory access device', besides the CPU itself.
Hardware can access parts of memory through this chip (when they have
permission), and the CPU can tell the DMA-chip to write memory to hardware
(the other way around).

Without DMA, the CPU has to fetch/write every byte (okay, maybe multiple
bytes) by itself, which costs quite some cycles (waiting for the device to
be finnished writing for example). Preparing the data in memory and then
giving a single 'put it to disk'-commmand hogs less CPU.

	Henk Poley <><