As I mentioned a couple months ago, CodeSourcery is interested in 
extending tracepoints, most notably to make them be more like 
breakpoints with conditionals and such. We're also planning to add 
"trace state variables", which are kind of like convenience variables 
managed by the target's agent, and a file format for raw trace data 
stored offline. Things are still in the planning stage (I've been madly 
hacking to get a basic stub running), so everything is still tweakable, 
and feel free to comment on lamenesses or omissions. This first bit 
takes the form of a patch to GDB's tracepoint chapter, so it should be 
read with an eye to how user will learn how to use tracepoints.

Stan