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.
| Feature | Restriction |
|---|---|
| No checksum offloads | Checksums must be done in the host. |
| No pacing | 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. |