Applications are unaffected, Onload deals with underlying architectural differences, and the data visible to the application via the sockets API is unaffected.
The following architectural differences affect receive:
- Maximum of 256 filters.
- Filtering is by 3-tuple (remote IP address and port).
- No receive-side scaling.
The following architectural differences affect transmit:
- Maximum of 15 applications for unshared TX queues (16 queues).
- All transmission is by reliable CTPIO with stable performance.
- No hardware checksums.
- Frequent polling is essential to achieve reasonable packet rate due to small transmit buffer in hardware.
The following difference affect tuning:
- On X3522 the
xilinx_efctnet driver must perform regular work to keep the RX path supplied with buffers, including when using Onload/TCPDirect/ef_vi.
- Ensure that
xilinx_efctinterrupts are delivered to CPU cores that have sufficient capacity and can be handled in a timely fashion to avoid underruns.
For more detailed information about X3-series adapters and their differences from predecessors, see the Alveo X3522 User Guide (UG1523).