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Ixiasoft
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Ixiasoft
4.5. TPH/ATS Capabilities
TLP Processing Hints (TPH) Overview
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 MSI-X Table or a custom location. 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.
Address Translation Services (ATS) Overview
ATS extends the PCIe protocol to support an address translation agent (TA) that translates DMA addresses to cached addresses in the device. The translation agent can be located in or above the Root Port. Locating translated addresses in the device minimizes latency and provides a scalable, distributed caching system that improves I/O performance. The Address Translation Cache (ATC) located in the device reduces the processing load on the translation agent, enhancing system performance. For more information about ATS, refer to Address Translation Services Revision 1.1
Parameter |
Value |
Description |
---|---|---|
Enable Address Translation Services | On/Off | When On, the PF supports ATS. |
Enable TLP Processing Hints (TPH) |
On/Off |
When On, the PF supports TPH. |
Interrupt Mode | On/Off |
When On, an MSI-X interrupt vector number selects the steering tag. |
Device Specific Mode | On/Off |
When On, the TPH Requestor Capability structure stores the steering tag table. |
Steering Tag Table Location | ST table not present MSI-X table |
When On, the MSI-X table stores the steering tag table . |
Steering Tag Table size | 0-2047 | Specifies the number of 2-byte steering table entries. |
Parameter |
Value |
Description |
---|---|---|
Enable Address Translation Services | On/Off | When On, the PF supports ATS. |
Enable TLP Processing Hints (TPH) |
On/Off |
When On, the PF supports TPH. |
Interrupt Mode | On/Off |
When On, an MSI-X interrupt vector number selects the steering tag. |
Device Specific Mode | On/Off |
When On, the TPH Requestor Capability structure stores the steering tag table. |
Steering Tag Table Location | ST table not present MSI-X table |
Selects the location of the steering tag table in Device Specific Mode is On. |
Steering Tag Table size | 0-2047 | Specifies the number of 2-byte steering table entries. |