The very low-latency CTPIO transmit path comes at a sacrifice of some of the adapter acceleration features:
The following adapter features are not available to packets sent via CTPIO.
|No checksum offloads
|Checksums must be done in the host.
|Packet is sent as soon as last descriptor is posted.
|No switch loopback
|No HW loopback of packets to local receivers.
|No filter drop
|No loopback packets to local receivers and CTPIO packets are not subject to any TX drop filters.
No flow control
No Qbb flow control
CTPIO traffic cannot be subject to pause frames or priority flow control measures.
Pause frames received at the CTPIO sender will have no effect.