Arria® 10 Avalon® Streaming with SR-IOV IP for PCIe* User Guide

ID 683686
Date 9/12/2024
Public
Document Table of Contents

3.7. Physical Function TLP Processing Hints (TPH)

TPH support PFs that target a TLP towards a specific processing resource such as a host processor or cache hierarchy. Steering Tags (ST) provide design-specific information about the host or cache structure.
Software programs the Steering Tag values that are stored in an ST table. You can store the ST Table in the TPH Requestor Capability structure or combine it with the MSI-X Table. For more information about Steering Tags, refer to Section 6.17.2 Steering Tags of the PCI Express Base Specification, Rev. 3.0. After analyzing the traffic of your system, you may be able to use TPH hints to improve latency or reduce traffic congestion.
Table 14.  TPH CapabilitiesThe values specified here are common for all PFs.

Parameter

Value

Description

Interrupt Mode On/Off

When On, the Steering Tag is selected by an MSI/MSI-X interrupt vector number.

Device Specific Mode

On/Off

When On, the Steering Tag is selected from Steering Tag Table entry stored in the TPH Requestor Capability structure.

Steering Tag Table location

0, 1, 2

When non-zero, specifies the location of the Steering Tag Table. The following encodings are defined:
  • 0: Steering Tag table not present
  • 1: Steering Tag table is stored in the TPH Requestor Capability structure
  • 2: Steering Tag table is located in the MSI-X table.

Steering Tag Table size

0-2047

Specifies the number of 2-byte Steering Table entries.