[LUGSB] Kernel related question

[Sean Callanan]

Mark's description is right on the ball, as far as I can tell :)

Only thing I'd add is you don't just get better UI responsiveness. 
Certain classes of threads which need to do things at particular 
intervals, and preferably exactly at those intervals, also benefit.

An example of such a thread is an MP3 player (this one gets mentioned 
every time the topic comes up, but I'll kick the dead horse once more). 
It wants to send some data to the sound card at specific intervals, so 
that the audio won't be jerky. If your MP3 player happens to want to 
send some data at the same time that slocate (for instance) is in the 
system, then the system call slocate is in will be preempted and the 
MP3 player will be allowed to send its data.

Of course, this isn't a panacea: every thread that gets priority means 
a thread that had to wait, but this way you get more control over how 
latency is distributed between processes.

Sincerely,
Sean Callanan