Transaction abort processing

• US 9,354,925 B2
• Filed: 03/08/2013
• Issued: 05/31/2016
• Est. Priority Date: 06/15/2012
• Status: Active Grant

• Current Assignee: International Business Machines Corporation
• Original Assignee: International Business Machines Corporation
• Inventors: Greiner, Dan F., Jacobi, Christian, Slegel, Timothy J.
• Primary Examiner(s): Kim, Sisley
• Application Number:
  US13/790,020
• Publication Number:
  US 20130339962A1
• Time in Patent Office: 1,180 Days
• Field of Search: None
• US Class Current: 1/1
• CPC Class Codes: G06F 9/3004 to perform operations on memory
• CPC Class Codes: G06F 9/30087 Synchronisation or serialisation instructions
• CPC Class Codes: G06F 9/30098 Register arrangements
• CPC Class Codes: G06F 9/30145 Instruction analysis, e.g. decoding, instruction word fields
• CPC Class Codes: G06F 9/3834 Maintaining memory consistency
• CPC Class Codes: G06F 9/3842 Speculative instruction execution
• CPC Class Codes: G06F 9/3858 Result writeback, i.e. updating the architectural state or memory
• CPC Class Codes: G06F 9/3861 Recovery, e.g. branch miss-prediction, exception handling error detection or correction G06F11/00
• CPC Class Codes: G06F 9/466 Transaction processing

Abstract

A transaction executing within a computing environment ends prior to completion; i.e., execution is aborted. Pursuant to aborting execution, a hardware transactional execution CPU mode is exited, and one or more of the following is performed: restoring selected registers; committing nontransactional stores on abort; branching to a transaction abort program status word specified location; setting a condition code and/or abort code; and/or preserving diagnostic information.

Claims

1. A method of facilitating processing in a computing environment, said method comprising:

initiating, by a processor, execution of an outermost transaction via a transaction begin instruction, the outermost transaction causing the processor to enter transactional execution mode, the transaction begin instruction including a field having a general register save mask, the general register save mask specifying which individually selected registers, if any, are to be saved at a beginning of transactional execution mode and restored on an abort;

aborting, by the processor, execution of a transaction of the transactional execution mode executing within the computing environment, the transaction effectively delaying committing transactional stores to main memory until completion of a selected transaction, the aborting terminating execution of the transaction prior to completion; and

based on aborting execution of the transaction, identifying one or more selected registers to be restored, the one or more selected registers being less than all of the registers used in transactional processing associated with the transaction, and the one or more selected registers being pre-specified by the general register save mask, wherein the general register save mask includes a plurality of bits, each bit corresponding to one or more registers, and wherein a bit of the plurality of bits set to a first value indicates that the one or more registers corresponding to that bit are to be saved during the beginning of transactional execution mode and restored based on the abort of the transaction executing in the transactional execution mode.

2. The method of claim 1, further comprising restoring the one or more selected registers.

3. The method of claim 1, wherein the one or more selected registers are indicated in an instruction initiating the transaction, or in an instruction initiating another transaction, the another transaction and the transaction being nested transactions.

4. The method of claim 1, further comprising committing nontransactional stores based on the aborting.

5. The method of claim 1, further comprising proceeding to a transaction abort program status word specified location to perform an action, based on the aborting.

6. The method of claim 5, wherein the transaction comprises a constrained transaction, and wherein the transaction abort program status word specified location comprises a beginning of the constrained transaction.

7. The method of claim 5, wherein the transaction comprises a nonconstrained transaction, and wherein the transaction abort program status word specified location comprises an instruction following a beginning of the nonconstrained transaction.

8. The method of claim 1, wherein based on aborting execution, the method further comprises setting a condition code, the condition code to indicate whether re-execution of the transaction is recommended.

9. The method of claim 1, wherein based on aborting execution providing an abort code, the abort code to indicate a cause for aborting execution.

10. The method of claim 1, further comprising storing diagnostic information, based on aborting execution.

11. The method of claim 1, wherein the aborting is based on detection of a transactional conflict.