Providing a fine-grained arbitration system

• US 8,667,197 B2
• Filed: 09/08/2010
• Issued: 03/04/2014
• Est. Priority Date: 09/08/2010
• Status: Expired due to Fees

• Current Assignee: Intel Corporation
• Original Assignee: Intel Corporation
• Inventors: Lai, Siaw Kang
• Primary Examiner(s): Myers, Paul R
• Application Number:
  US12/877,871
• Publication Number:
  US 20120059962A1
• Time in Patent Office: 1,273 Days
• Field of Search: 710113-124, 710240-244
• US Class Current: 710/113
• CPC Class Codes: G06F 13/3625 using a time dependent access
• CPC Class Codes: G06F 13/364 using independent requests or grants, e.g. using separated request and grant lines

Abstract

In one embodiment, the present invention includes a method for selecting a requester to service during an arbitration round, and updating counters associated with the selected requester including a command unit counter and a data unit counter, determining if the counters are in compliance with corresponding threshold values, and if so granting a transaction for the selected requester, and otherwise denying the transaction. Other embodiments are described and claimed.

Claims

1. A method comprising:

selecting one of a plurality of requesters for servicing, and thereafter updating a first counter and a second counter associated with the selected requester, wherein the first counter corresponds to a command unit counter to maintain a first count value associated with a command portion of a transaction and the second counter corresponds to a data unit counter to maintain a second count value associated with a data portion of the transaction;

determining if each of the first and second counters are in compliance with a corresponding threshold value for the first and second counters; and

if so, granting a transaction for the selected requester, and otherwise denying the transaction for the selected requester.

2. The method of claim 1, further comprising updating the first counter and the second counter based on the transaction.

3. The method of claim 2, further comprising selecting the selected requester based on a priority level of the selected requester and a priority level of each of the plurality of requesters.

4. The method of claim 1, further comprising granting a consecutive plurality of transactions for the selected requester, while at least one other requester is not granted any transactions.

5. The method of claim 4, further comprising iteratively updating the first and second counters after each of the consecutive plurality of transactions.

6. The method of claim 5, further comprising granting the consecutive plurality of transactions until at least one of the first and second counters is not in compliance with the corresponding threshold.

7. The method of claim 1, further comprising responsive to the at least one of the first and second counters not being in compliance with the corresponding threshold, selecting a second requester to service.

8. The method of claim 1, wherein the first counter is not in compliance if it reaches a zero value, and the second counter is not in compliance if it reaches a zero value or a negative value.

9. The method of claim 8, further comprising debiting the second counter by an amount of the negative value at a beginning of a next arbitration round.

10. The method of claim 1, further comprising assigning a fraction of service for an arbitration round to each of the plurality of requesters.

11. An apparatus comprising:

a first counter circuit including a plurality of first counters each associated with a requester and to store a count of command units allocated to the corresponding requester, each of the command units corresponding to a command portion of a transaction;

a second counter circuit including a plurality of second counters each associated with a requester and to store a count of data units allocated to the corresponding requester, each of the data units corresponding to a data portion of a transaction; and

an arbiter coupled to the first and second counter circuits to select one of the plurality of requesters to service and to grant a transaction of the requester access to a shared interconnect if the first and second counters associated with the selected requester are in compliance with a corresponding threshold value, and otherwise to deny the transaction of the requester.

12. The apparatus of claim 11, wherein the apparatus comprises a system-on-a-chip including a plurality of agents each corresponding to one of the requesters, and wherein granted transactions are to be communicated on the shared interconnect.

13. The apparatus of claim 11, wherein the arbiter is to grant a consecutive plurality of transactions for the selected requester, while at least one other requester is not granted any transactions.

14. The apparatus of claim 13, wherein the arbiter is to iteratively update the first and second counters after each of the consecutive plurality of transactions, and grant the consecutive plurality of transactions until at least one of the first and second counters is not in compliance with the corresponding threshold.

15. The apparatus of claim 11, further comprising a controller coupled to the arbiter, wherein the controller is to adjust a fraction of service allocated to at least some of the plurality of requesters based on requester consumption information.

16. The apparatus of claim 15, wherein the controller is to dynamically adjust the fraction of service.

17. The apparatus of claim 15, wherein the controller is to determine if the requester consumption information indicates that consumption is within a consumption policy limit, and to adjust the fraction of service if the consumption is not within the consumption policy limit.

18. A system comprising:

a first agent to perform operations on data;

a second agent to perform operations on data;

a shared interconnect coupled to the first and second agents;

a command unit counter to store a count of command units allocated to the first and second agents, each of the command units corresponding to a command portion of a transaction;

a data unit counter to store a count of data units allocated to the first and second agents, each of the data units corresponding to at least a part of a data portion of a transaction; and

an arbiter coupled to the command unit counter and the data unit counter, and to select one of the first and second agents to enable access to the shared interconnect if the command unit counter and the data unit counter associated with the selected agent are above a corresponding threshold value, and otherwise to prevent the access to the shared interconnect by the selected agent.

19. The system of claim 18, wherein the arbiter is to grant a consecutive plurality of transactions of the selected agent access to the shared interconnect, while transactions of the other agent are not granted access to the shared interconnect.

20. The system of claim 18, further comprising a controller coupled to the arbiter, wherein the controller is to dynamically adjust a fraction of service allocated to the first and second agents based on comparison of consumption information of the first and second agents to corresponding consumption policy limits.