cptracer probes can measure latency, throughput, and describe transactions.

The probes measure over a sample period. The default value in the Period
filed is 0x3FFF.  For example the MSMC1 probe period can be changed by:
      cptracer.MSMC1.EMIF0_I.PERiod 0x<value>.

The value represents bits 23-10 of a 24 bit filed. Bits 9:0 are fixed
at 0x1F.  A probe's speed is typically set to match the speed of the 
interconnect its connected to. For example the MSMC (and C7x) run
typically run at 1GHz.

The default probe counter will accumulate events over the interval of:
0x00FFFFFF * 1/1GHz = 16.7mS

To find average throughput use (total bytes / time in sample period)
To find the average transaction length use (total bytes / total matched)

To find average latency use (total wait time) / (total tracked)

First usage typically is broad total usage.  However, zooming in is possible
by using routeid and address filtering.

Since multiple routes exist to some destinations traffic monitoring may be needed
multiple points to get a full picture.

Todo: Add typical probe clock speeds