Packet Buffers

Onload User Guide (UG1586)

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1.2 English

This chapter describes packet buffers on SFN8000 series and X2 series adapters. For a description of packet buffers and CTPIO on X3 series adapters refer to the Alveo X3522 User Guide (UG1523).

Packet buffers describe the memory used by the Onload stack (and network adapter) to receive, transmit and queue network data. Packet buffers provide a method for user-mode accessible memory to be directly accessed by the network adapter without compromising system integrity.

Onload will request huge pages if these are available when allocating memory for packet buffers. Using huge pages can lead to improved performance for some applications by reducing the number of Translation Lookaside Buffer (TLB) entries needed to describe packet buffers and therefore minimize TLB ‘thrashing’.

Note: Onload huge page support should not be enabled if the application uses IPC namespaces and the CLONE_NEWIPC flag.

Onload offers two configuration modes for network packet buffers: