Run-time instrumentation sampling in transactional-execution mode

• US 9,372,693 B2
• Filed: 03/07/2013
• Issued: 06/21/2016
• Est. Priority Date: 03/16/2012
• Status: Active Grant

• Current Assignee: International Business Machines Corporation
• Original Assignee: International Business Machines Corporation
• Inventors: Bradbury, Jonathan D., Gainey, Charles W. Jr., Gschwind, Michael K.
• Primary Examiner(s): Zhen, Wei
• Assistant Examiner(s): HUDA, MOHAMMED NURUL
• Application Number:
  US13/788,490
• Publication Number:
  US 20130246775A1
• Time in Patent Office: 1,202 Days
• Field of Search: 717/130
• US Class Current: 1/1
• CPC Class Codes: G06F 11/3466 Performance evaluation by tracing or monitoring
• CPC Class Codes: G06F 11/348 Circuit details, i.e. tracer hardware
• CPC Class Codes: G06F 11/3612 by runtime analysis performance monitoring G06F11/3466
• CPC Class Codes: G06F 11/362 Software debugging
• CPC Class Codes: G06F 11/3664 Environments for testing or debugging software
• CPC Class Codes: G06F 2201/86 Event-based monitoring
• CPC Class Codes: G06F 2201/87 Monitoring of transactions
• CPC Class Codes: G06F 9/3005 to perform operations for flow control
• CPC Class Codes: G06F 9/30058 Conditional branch instructions
• CPC Class Codes: G06F 9/30145 Instruction analysis, e.g. decoding, instruction word fields
• CPC Class Codes: G06F 9/45533 Hypervisors; Virtual machine monitors

Abstract

Embodiments of the invention relate to implementing run-time instrumentation sampling in transactional-execution mode. An aspect of the invention includes a method for implementing run-time instrumentation sampling in transactional-execution mode. The method includes determining, by a processor, that the processor is configured to execute instructions of an instruction stream in a transactional-execution mode, the instructions defining a transaction. The method also includes interlocking completion of storage operations of the instructions to prevent instruction-directed storage until completion of the transaction. The method further includes recognizing a sample point during execution of the instructions while in the transactional-execution mode. The method additionally includes run-time-instrumentation-directed storing, upon successful completion of the transaction, run-time instrumentation information obtained at the sample point.

Claims

1. A computer implemented method for implementing run-time instrumentation sampling in transactional-execution mode, the method comprising:

determining, by a processor, that the processor is configured to execute instructions of an instruction stream in a transactional-execution mode, the instructions defining a transaction;

interlocking completion of storage operations of the instructions to prevent instruction-directed storage until completion of the transaction;

collecting run-time instrumentation events in a collection buffer while in the transactional-execution mode, the collection buffer located within the processor, wherein the run-time instrumentation events are events recognized by the processor during execution of the instructions;

recognizing a sample point during execution of the instructions while in the transactional-execution mode, the sample point corresponding to an instruction executed inside of the transaction;

run-time-instrumentation-directed storing, upon successful completion of the transaction, run-time instrumentation information obtained at the sample point; and

performing the run-time-instrumentation-directed storing as a non-transactional store of a reporting group based on the run-time instrumentation events in the collection buffer to a run-time instrumentation program buffer in a main memory.

2. The method of claim 1, wherein run-time-instrumentation-directed storing the run-time instrumentation information obtained at the sample point further comprises:

deferring storage of the run-time instrumentation events as the reporting group in the run-time instrumentation program buffer while in the transactional-execution mode; and

side-effect storing the reporting group in the run-time instrumentation program buffer based on the completion of the transaction.

3. The method of claim 1, wherein run-time-instrumentation-directed storing the run-time instrumentation information obtained at the sample point further comprises:

storing the reporting group comprising the run-time instrumentation information in a transactional-execution scratchpad buffer; and

deferring storage of the reporting group from the transactional-execution scratchpad buffer to the run-time instrumentation program buffer while in the transactional-execution mode.

4. The method of claim 3, further comprising:

recognizing a subsequent sample point during execution of the instructions while in the transactional-execution mode;

run-time-instrumentation-directed storing subsequent run-time instrumentation information obtained at the subsequent sample point as a subsequent reporting group in the transactional-execution scratchpad buffer;

deferring storage of the subsequent reporting group in the run-time instrumentation program buffer while in the transactional-execution mode; and

side-effect storing the reporting group and the subsequent reporting group from the transactional-execution scratchpad buffer to the run-time instrumentation program buffer based on the completion of the transaction.

6. The method of claim 1, further comprising:

detecting a transaction abort event as a failure to successfully complete the transaction;

collecting a transaction abort record associated with the transaction abort event in the collection buffer; and

storing the reporting group containing the transaction abort record.

7. The method of claim 6, further comprising:

storing a transaction failure code in the transaction abort record to indicate a transaction failure reason.

8. The method of claim 1, wherein the sample point is identified based on one of:

cycle-count sampling, instruction-count sampling, indirect sampling, and directed sampling.

5. A computer implemented method for implementing run-time instrumentation sampling in transactional-execution mode, the method comprising:

determining, by a processor, that the processor is configured to execute instructions of an instruction stream in a transactional-execution mode, the instructions defining a transaction;

storing a copy of a program buffer current address pointing to a current location in a run-time instrumentation program buffer upon a transition from a non-transactional-execution mode to the transactional-execution mode;

interlocking completion of storage operations of the instructions to prevent instruction-directed storage until completion of the transaction;

recognizing a sample point during execution of the instructions while in the transactional-execution mode;

run-time-instrumentation-directed storing, upon successful completion of the transaction, run-time instrumentation information obtained at the sample point;

performing the run-time-instrumentation-directed storing as a non-transactional store of a reporting group written to the program buffer current address;

updating the program buffer current address based on the storing the reporting group;

detecting a transaction abort event associated with the transaction;

restoring the program buffer current address to the copy of the program buffer current address upon detecting the transaction abort event; and

storing a transaction abort record associated with the transaction abort event in a next reporting group in the run-time instrumentation program buffer.