On the X2 series adapter, CTPIO is enabled by default in sf-np mode. The following Onload environment variables are used to configure CTPIO:
| EF Variable | Settings |
|---|---|
EF_CTPIO
|
0 disable 1 enable (default) 2 enable, fail if not available |
EF_CTPIO_MODE
|
ct cut-through mode (not supported for 25 Gb) sf store-and-forward mode sf-np store-and-forward-no-poison (default) |
EF_CTPIO_MAX_FRAME_LEN
|
Integer value Packets with length exceeding this value are not sent via CTPIO, but are sent using the legacy DMA datapath. |
Latency-best Profile
Onload-201805 includes a new low latency profile that enables CTPIO in cut-through mode to deliver lowest CTPIO latency:
# onload --profile=latency-best <application, args>Before using this profile, please read The latency-best Profile, especially the warning on usage.