Philip Covington wrote:
...One interesting thing is that if you just compile the 2.6 kernel with CONFIG_PREEMPT then it's soft realtime enough that I would almost say that there is no need for RTAI in the SDR application. This is a huge change from the last time I played with these things using the 2.4 kernel...
There's been a tremendous amount of pressure to get this right in 2.6, mostly from the people developing DAW packages. Think ardour, with N-channel full duplex hd recording/playback/mixing/plugins.
What you hear from the audio guys is that soft realtime, all by itself, is almost there.
The biggest obstacles we've run into are (1) X servers niced artificially low, and (2) once-per-second disk sync. The first translates to paging glitches, the second to queued network IO, a lot of it loopback and local.
On a pared down system, with a lot of physical memory and running off ram disk, it looks like both those problems can merely be configured out of existence without further tweaking. This isn't an option for the DAW apps, so it's reasonable to expect further hammering on soft realtime.
Frank
