Method and system for a sharing buffer

• US 8,131,894 B2
• Filed: 11/23/2009
• Issued: 03/06/2012
• Est. Priority Date: 11/27/2008
• Status: Expired due to Fees

• Current Assignee: International Business Machines Corporation
• Original Assignee: International Business Machines Corporation
• Inventors: Cain, Harold Wade III, Hou, Rui, Shen, Xiaowei, Wang, Huayong
• Primary Examiner(s): Lee, Chun-Kuan
• Assistant Examiner(s): MARTINEZ, DAVID E
• Application Number:
  US12/623,496
• Publication Number:
  US 20100138571A1
• Time in Patent Office: 834 Days
• Field of Search: 710/52, 710/56
• US Class Current: 710/52
• CPC Class Codes: G06F 9/30087 Synchronisation or serialisation instructions
• CPC Class Codes: G06F 9/467 Transactional memory G06F9/528 takes precedence
• CPC Class Codes: G06F 9/5016 the resource being the memory

Abstract

A system, method, and computer readable article of manufacture for sharing buffer management. The system includes: a predictor module to predict at runtime a transaction data size of a transaction according to history information of the transaction; and a resource management module to allocate sharing buffer resources for the transaction according to the predicted transaction data size in response to beginning of the transaction, to record an actual sharing buffer size occupied by the transaction in response to the successful commitment of the transaction, and to update the history information of the transaction.

Claims

1. A sharing buffer management system, comprising:

a predictor module to predict at runtime a transaction data size of a transaction according to history information of the transaction; and

a resource management module to allocate sharing buffer resources for the transaction according to the predicted transaction data size in response to beginning of the transaction, to record an actual sharing buffer size occupied by the transaction in response to the successful commitment of the transaction and update the history information of the transaction.

2. The system according to claim 1, wherein:

the predictor module increases said predicted transaction data size by a predetermined value in response to the transaction overflowing the allocated sharing buffer resources and uses the increased predicted transaction data size as a new predicted transaction data size; and

the resource management module allocates sharing buffer resources for the transaction according to the new predicted transaction data size.

3. The system according to claim 1, wherein the resource management module is configured to:

compare said predicted transaction data size with currently available resources of said sharing buffer;

allocate sharing resources which are equal to the predicted transaction data size for the transaction in response to having enough sharing buffer resources; and

allocate no sharing resources for the transaction and reject the beginning of the transaction in response to not having enough sharing buffer resources for the transaction.

4. The system according to claim 1, wherein the resource management module directs the transaction to special handling for transaction overflow in response to said predicted transaction data size being larger than said sharing buffer resources.

5. The system according to any one of claim 1, wherein the predictor module is configured to predict a transaction data size using at least one of latest value prediction, average value prediction, maximum value prediction, and amplitude simulation prediction.

6. The system according to claim 1, wherein the history information of said transaction comprises a two-level software hash table, wherein the first level is indexed by thread identification and the second level is indexed by transaction address.

7. The system according to claim 1, further comprising:

a cache way in said sharing buffer consisting of a color register for storing a color flag for the transaction.

8. The system according to claim 7, wherein said predictor module is configured to predict a transaction data size for a transaction at the granularity of the cache way and said resource management module is configured to allocate sharing buffer resources at the granularity of the cache way.

9. The system according to claim 1, wherein the sharing buffer comprises:

a plurality of associated cache ways, wherein each of the cache ways has a plurality of cache lines;

an address index for addressing cache lines at locations in each cache way;

a color register for storing a color value for each cache way, wherein each color value corresponds to a transaction, and

wherein said sharing buffer is configured to share buffer resources among multiple transactions at the granularity of the cache way.

10. A method implemented by a computing apparatus for managing a sharing buffer, the method comprising the steps of:

predicting at runtime by a predictor module a transaction data size of a

transaction according to history information of the transaction;

allocating sharing buffer resources for the transaction by a resource management module according to the predicted transaction data size in response to beginning of the transaction;

recording by the resource management module an actual sharing buffer size occupied by the transaction in response to the successful commitment of the transaction; and

updating the history information of the transaction by the resource management module, thereby managing the sharing buffer by the computing apparatus.

11. The method according to claim 10, further comprising:

increasing by the predictor module, said predicted transaction data size by a predetermined value in response to the transaction overflowing the allocated sharing buffer resources;

using the increased predicted transaction data size by the predictor module as a new predicted transaction data size;

allocating, by the resource management module, sharing buffer resources for the transaction according to the new predicted transaction data size; and

restarting the transaction.

12. The method according to claim 10, wherein the step of allocating sharing buffer resources by the resource management module further comprises:

comparing said predicted transaction data size with currently available resources of said sharing buffer;

allocating sharing resources which are equal to the predicted transaction data size for the transaction in response to having enough sharing buffer resources for the transaction;

in response to not having enough sharing buffer resources for the transaction, allocating no sharing resources for the transaction; and

when no sharing resources are allocated, rejecting the beginning of the transaction.

13. The method according to claim 10, further comprising:

directing the transaction by the resource management module to special handling for transaction overflow in response to said predicted transaction data size being larger than said sharing buffer resources.

14. The method according to claim 10, wherein predicting the transaction data size by the predictor module uses at least one of a latest value prediction, an average value prediction, a maximum value prediction, and an amplitude simulation prediction.

15. The method according to claim 10, further comprising:

configuring the history information of said transaction as a two-level software hash table, wherein the first level is indexed by thread identification and the second level is indexed by transaction address.

16. The method according to claim 10, further comprising:

configuring a color register for a cache line in said sharing buffer; and

storing a color flag for a transaction in said color register.

17. The method according to claim 16, wherein the step of predicting a transaction data size for a transaction is performed at granularity of the cache line, and the step of allocating sharing buffer resources is performed at granularity of the cache line.

18. A computer readable article of manufacture tangibly embodying computer readable instructions which, when executed, cause a computing apparatus to implement a method for managing a sharing buffer, comprising:

predicting at runtime by a predictor module a transaction data size of a transaction according to history information of the transaction;

allocating sharing buffer resources for the transaction by a resource management module according to the predicted transaction data size in response to beginning of the transaction;

recording by the resource management module an actual sharing buffer size occupied by the transaction, in response to the successful commitment of the transaction; and

updating the history information of the transaction by the resource management module.