Tracking transactional execution footprint

• US 9,262,320 B2
• Filed: 06/15/2012
• Issued: 02/16/2016
• Est. Priority Date: 06/15/2012
• Status: Expired due to Fees

• Current Assignee: International Business Machines Corporation
• Original Assignee: International Business Machines Corporation
• Inventors: Alexander, Khary J., Hsieh, Jonathan T., Jacobi, Christian, West, Patrick M.
• Primary Examiner(s): Savla, Arpan P.
• Application Number:
  US13/524,355
• Publication Number:
  US 20130339629A1
• Time in Patent Office: 1,341 Days
• Field of Search: 711/124, 711/141, 711/144, 711/150, 711/152, 711/154, 711/156, 711/168, 711/E12.037, 710/36, 710/48, 710/52
• US Class Current: 1/1
• CPC Class Codes: G06F 12/08 in hierarchically structured memory systems, e.g. virtual memory systems
• CPC Class Codes: G06F 12/0815 Cache consistency protocols
• CPC Class Codes: G06F 12/084 with a shared cache
• CPC Class Codes: G06F 9/30 Arrangements for executing machine instructions, e.g. instruction decode for executing microinstructions G06F9/22
• CPC Class Codes: G06F 9/3004 to perform operations on memory
• CPC Class Codes: G06F 9/30043 LOAD or STORE instructions; Clear instruction
• CPC Class Codes: G06F 9/30087 Synchronisation or serialisation instructions
• CPC Class Codes: G06F 9/3013 according to data content, e.g. floating-point registers, address registers
• CPC Class Codes: G06F 9/3834 Maintaining memory consistency
• CPC Class Codes: G06F 9/38585 with result invalidation, e.g. nullification
• CPC Class Codes: G06F 9/466 Transaction processing
• CPC Class Codes: G06F 9/467 Transactional memory G06F9/528 takes precedence

Abstract

Embodiments relate to tracking a transactional execution footprint. An aspect includes receiving a store instruction which includes store data. It is determined if the store instruction is executing within a transaction that effectively delays committing stores to a shared cache until the transaction has completed. The store data is stored to a cache line in a local cache. The cache line is marked as dirty if the transaction is active. The stored data that was marked as dirty in the local cache is invalidated if the transaction has terminated abnormally. The stored data is un-marked if it is determined that the transaction has successfully ended.

Claims

1. A system for tracking a transactional execution footprint, the system comprising:

a processing circuit configured to perform a method comprising;

receiving a store instruction, the store instruction including store data;

setting a write enable flag based on receiving the store instruction;

determining that the store instruction is executing within a transaction wherein the transaction effectively delays committing stores to a shared cache until completion of the transaction;

buffering the store data in a local storage buffer;

storing the store data to a cache line in a local cache and marking the cache line as dirty based on determining that the transaction is active and the write enable flag is set;

invalidating stored data marked as dirty in the local cache based on determining that the transaction has terminated abnormally;

tracking in the local storage buffer that the transaction has terminated abnormally;

disabling the write enable flag for the store data based on determining that the transaction has terminated abnormally;

preventing the store data from being transmitted to the local cache based on determining that the write enable flag is disabled;

preventing a pending indicator associated with the store data to mark the cache line as dirty from being set based on the write enable flag being disabled; and

un-marking stored data based on determining that the transaction has successfully ended.

2. The system of claim 1, further comprising buffering and transmitting the store data to a next level cache based on determining that that the transaction has completed successfully.

3. The system of claim 1, wherein the store instruction is transactional if it occurs after a transaction begin instruction and before the transaction terminates.

4. The system of claim 1, further comprising tracking, using a pending indicator, the transmitted store data based on determining that the store instruction is transactional, wherein the pending indicator is stored in a cache directory of the local cache.

5. The system of claim 1, wherein the invalidating of the store data further comprises invalidating the cache line in a cache directory by invalidating a validate bit of the cache line.

6. The system of claim 1, wherein the invalidating of the store data further comprises reverting the cache line by refetching the cache line from a next level cache.

7. A method for tracking a transactional execution footprint comprising:

receiving, by a processing circuit, a store instruction, the store instruction including store data;

setting a write enable flag based on receiving the store instruction;

determining that the store instruction is executing within a transaction wherein the transaction effectively delays committing stores to a shared cache until completion of the transaction;

buffering the store data in a local storage buffer;

storing the store data to a cache line in a local cache and marking the cache line as dirty based on determining that the transaction is active and the write enable flag is set;

invalidating stored data marked as dirty in the local cache based on determining that the transaction has terminated abnormally;

tracking in the local storage buffer that the transaction has terminated abnormally;

disabling the write enable flag for the store data based on determining that the transaction has terminated abnormally;

preventing the store data from being transmitted to the local cache based on determining that the write enable flag is disabled;

preventing a pending indicator associated with the store data to mark the cache line as dirty from being set based on the write enable flag being disabled; and

un-marking stored data based on determining that the transaction has successfully ended.

8. The method of claim 7, further comprising buffering and transmitting the store data to a next level cache based on determining that that the transaction has completed successfully.

9. The method of claim 7, wherein the store instruction is transactional if it occurs after a transaction begin instruction and before the transaction terminates.

10. The method of claim 7, further comprising tracking, using a pending indicator, the transmitted store data based on determining that the store instruction is transactional, wherein the pending indicator is stored in a cache directory of the local cache.

11. The method of claim 7, wherein the invalidating of the store data further comprises invalidating the cache line in a cache directory by invalidating a validate bit of the cache line.

12. The method of claim 7, wherein the invalidating of the store data further comprises reverting the cache line by refetching the cache line from a next level cache.

13. A computer program product for tracking a transactional execution footprint said computer program product comprising:

a non-transitory computer readable storage medium readable by a processing circuit and storing instructions for execution by the processing circuit for performing a method comprising;

receiving, by a processing circuit, a store instruction, the store instruction including store data;

setting a write enable flag based on receiving the store instruction;

determining that the store instruction is executing within a transaction wherein the transaction effectively delays committing stores to a shared cache until completion of the transaction;

buffering the store data in a local storage buffer;

storing the store data to a cache line in a local cache and marking the cache line as dirty based on determining that the transaction is active and the write enable flag is set;

tracking in the local storage buffer that the transaction has terminated abnormally;

disabling the write enable flag for the store data based on determining that the transaction has terminated abnormally;

preventing the store data from being transmitted to the local cache based on determining that the write enable flag is disabled;

preventing a pending indicator associated with the store data to mark the cache line as dirty from being set based on the write enable flag being disabled; and

invalidating stored data marked as dirty in the local cache based on determining that the transaction has terminated abnormally.

14. The computer program product of claim 13, further comprising un-marking stored data based on determining that the transaction has successfully ended.

15. The computer program product of claim 13, further comprising buffering and transmitting the store data to a next level cache based on determining that that the transaction has completed successfully.

16. The computer program product of claim 13, wherein the store instruction is transactional if it occurs after a transaction begin instruction and before the transaction terminates.