Details:

This applies to 9-port CPSW, 5-port CPSW, 3-port CPSW, and 2-port CPSW IET traffic.

In IET (Interspersed Express traffic), if a preempted packet was interrupted by an express packet, two things can occur:

1. If the express traffic is policed, the frame size for the preempted packets is applied to the express traffic policer. Assuming a policer was set up to rate schedule an express traffic stream, it would take a hit by the preempted packet size it interrupted. The preempted packet also takes on the express traffic policer status. As a result, preempted packets could get dropped along with other express traffic due to the express traffic policer.
2. If the express traffic was not policed, the interrupted preempt packet would not get its packet size applied to the preempted policer.

Workaround(s):

Do not police IET express traffic.