63:38

0h

RO

Reserved

37:36

0h

RW/L

Batch Descriptors in Progress limit (BDIPL)

This field controls the number of batch descriptors that can be concurrently processed by an engine in the group as a fraction of the Maximum Batch Descriptors in Progress value specified in ENGCAP. Note that exercising this control can cause bandwidth to be reduced in some cases, depending on prevailing system latency. This field is reserved if the Descriptors in Progress Limit Supported field is GRPCAP is 0.
00: Allow up to the maximum value that an engine is capable of.
01: Limit to 1/2 of the maximum value.
10: Limit to 1/4 of the maximum value.
11: Limit to 1/8 of the maximum value.

35:34

0h

RO

Reserved

33:32

0h

RW/L

Work descriptors in progress limit (WDIPL)

This field controls the number of work descriptors that can be concurrently processed by an engine in the group as a fraction of the Maximum Work Descriptors in Progress value specified in ENGCAP. Note that exercising this control can cause bandwidth to be reduced in some cases, depending on prevailing system latency. This field is reserved if the Descriptors in Progress Limit Supported field is GRPCAP is 0.
00: Allow up to the maximum value that an engine is capable of.
01: Limit to 1/2 of the maximum value.
10: Limit to 1/4 of the maximum value.
11: Limit to 1/8 of the maximum value.

31:28

0h

RO

Reserved

27:20

0h

RO/V

Bandwidth Tokens Allowed (BWTOKALLOW)

This field indicates the maximum number of Read Buffers that may be in use at one time by all engines in the group. This value can be used to limit the maximum bandwidth used by engines in the group. This value must be:
- greater than or equal to 4 times the number of engines in the group;
- greater than or equal to the Read Buffers Reserved field for thisgroup; and
- less than or equal to the sum of the Read Buffers Reserved field andthe number of non-reserved Read Buffers.
(The number of non-reserved Read Buffers is the Total Read Buffers field in GRPCAP minus the total of the Read Buffers Reserved fields for all groups.)
The default value of this field is the same as the value of the Total Read Buffers field in GRPCAP.
If the Read Buffer Controls Supported field in GRPCAP is 0, this field is read-only and is unused.

19:16

0h

RO

Reserved

15:8

0h

RO

Bandwidth Tokens Reserved (BWTOKRSVD)

This field indicates the number of Read Buffers reserved for the use of engines in the group. This value can be used to reduce the possibility of contention with engines in other groups. However, if it is set to a nonzero value, it may reduce the overall performance of the device. The sum of the Read Buffers reserved for all groups must be less than or equal to the Total Read Buffers field in GRPCAP.
If the Read Buffer Controls Supported field in GRPCAP is 0, this field is read-only and is unused.

7

0h

RO

Use Global Bandwidth Token Limit (UGBTL)

0: The Global Read Buffer Limit does not apply to this group.
1: The Global Read Buffer Limit programmed in the GENCFG register applies to descriptors processed by engines in this group. (The limit indicated by the Read Buffers Allowed field applies as well.)
If the Global Read Buffer Limit Supported field in GRPCAP is 0, this field is reserved.

6

0h

RO

Reserved

5:3

0h

RW/L

GRPFLAGS TC-B (TCB)

Specifies the traffic class to use for memory accesses for which the traffic class selector in the descriptor is 1.

2:0

0h

RW/L

GRPFLAGS TC-A (TCA)

Specifies the traffic class to use for memory accesses for which the traffic class selector in the descriptor is 0.