New KTR trace for mouse freezing/stuttering in 7.0-RC1

[Joe Peterson]

John Baldwin wrote:
> Hmm, when I look at that graph using schedgraphy from HEAD it just looks
> like xtrs is using up all the CPU.

Yeah, xtrs is eating a lot of CPU, but I've never seen this affect the
mouse movement (making it really jerky) the same way on, e.g., Linux.
And the xtrs test is just a way to *reliably* make it happen.  It
happens intermittently all of the time (at least every few minutes, and
often in small batches) even when the system is pretty idle...

					-Joe