Onload User Guide (UG1586)

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1.2 English

Onload-201805 introduces the Cut Through Programmed Input Output (CTPIO) feature to deliver the lowest send-path latency enabled by the architecture of the X2 series adapters. Packets are streamed directly over the PCIe bus to the network port, bypassing the main adapter transmit datapath.

CTPIO coexists alongside the standard host-buffered (DMA) transmit mechanism (Network Adapter Buffer Table Mode) and legacy PIO buffering (Programmed I/O). From an Onload VI, traffic using all three methods can be mixed on a frame-by-frame basis and per frame ordering is maintained. CTPIO delivers the lowest transmit latency.