Performance bttv versus sharedmem

["Keith Chew" <keith.chew@gmail.com>]

Hi

This is just a general question to understand where the improvement
can be made.

In the first setup, I have these processes:
- mencoder recording from bttv chip at 8 fps (cpu 3.5 %)
- mplayer playing from bttv chip at 10 fps (cpu 2.1 %)

In the second setup, I have these processes:
- mencoder recording from bttv to shared mem at 25 fps (cpu 1.7%)
- mencoder recording from shared mem at 8 fps (cpu 6.1%)
- mplayer playing from shared mem at 10 fps (cpu 3.1 %)

For the shared mem setup, the access to the memory is efficient, only
a memcopy to a buffer. Are the CPU usages inline with what you'd
expect, that the shared mem being almost 2 times the CPU usage? How
can I reduce the CPU usage in the shared mem setup?

Regards
Keith