Enabling end of transaction detection using speculative look ahead

Patent metadata

Field	Value
Publication number	US-2016350124-A1
Application number	US-201514722179-A
Country	US
Kind code	A1
Filing date	May 27, 2015
Priority date	May 27, 2015
Publication date	Dec 1, 2016
Grant date	—

Abstract

A transaction within a computer program or computer application comprises program instructions performing multiple store operations that appear to run and complete as a single, atomic operation. The program instructions forming a current transaction comprise a transaction begin indicator, a plurality of instructions (e.g., store operations), and a transaction end indicator. A near-end of transaction indicator is triggered based on a speculative look ahead operation such that an interfering transaction requiring a halt operation may be delayed to allow the current transaction to end. A halt operation, also referred to as an abort operation, as used herein refers to an operation responsive to a condition where two transactions have been detected to interfere where at least one transaction must be aborted and the state of the processor is reset to the state at the beginning of the aborted transaction by performing a rollback.

First claim

What is claimed is:

1 . A method for enabling end of transaction detection using speculative look ahead, the method comprising:
setting an indicator to indicate a current transaction is being processed; monitoring a speculative look ahead operation to detect whether an end-transaction instruction corresponding to the current transaction is likely to occur; and responsive to detecting the end-transaction instruction, enabling a near-end-transaction processing mode.

2 . The method of claim 1 , wherein the current transaction comprises a begin-transaction instruction and program instructions immediately following the begin-transaction instruction up to, and including, the end-transaction instruction, wherein the end-transaction instruction corresponds to the begin-transaction instruction.

3 . The method of claim 1 , wherein the speculative look ahead operation comprises decoding one or more program instructions prior to executing the one or more program instructions.

4 . The method of claim 1 , further comprising:
receiving a notification of an interference corresponding to the current transaction and a second computer process; and determining an interference action; wherein: the notification of the interference further includes an abort request for the current transaction.

5 . The method of claim 4 , wherein the interference action includes:
responsive to a request for a memory location, deferring a response to the request based on the indicating the end-transaction has been detected; and responsive to the notification of an interference, deferring a transaction abort.

6 . The method of claim 5 , further including
completing the current transaction; and providing a response to the request when the current transaction has completed.

7 . The method of claim 5 further including
determining a possibility of a deadlock; and
aborting the current transaction based on the possibility of a deadlock.

8 . The method of claim 1 , wherein enabling the near-end transaction processing mode includes modifying an execution behavior of the current transaction.

9 . The method of claim 8 , wherein modifying the execution behavior includes transmitting a near-end transaction indication.

10 . A computer program product for enabling end of transaction detection using speculative look ahead, the computer program product comprising a computer readable storage medium having stored thereon:
first program instructions programmed to set an indicator to indicate a current transaction is being processed; second program instructions programmed to monitor a speculative look ahead operation to detect whether an end-transaction instruction corresponding to the current transaction is likely to occur; and third program instructions programmed to, responsive to detecting the end-transaction instruction, enable a near-end-transaction processing mode.

11 . The computer program product of claim 10 , wherein the current transaction comprises a begin-transaction instruction and program instructions immediately following the begin-transaction instruction up to, and including, the end-transaction instruction, wherein the end-transaction instruction corresponds to the begin-transaction instruction.

12 . The computer program product of claim 10 , wherein the speculative look ahead operation comprises decoding one or more program instructions prior to executing the one or more program instructions.

13 . The computer program product of claim 10 , further comprising:
fourth program instructions programmed to receive a notification of an interference corresponding to the current transaction and a second computer process; and fifth program instructions programmed to determine an interference action; wherein: the notification of the interference further includes an abort request for the current transaction.

14 . The computer program product of claim 13 , wherein the interference action includes:
sixth program instructions programmed to, responsive to a request for a memory location, deferring a response to the request based on the indicating the end-transaction has been detected; and seventh program instructions programmed to, responsive to the notification of an interference, deferring a transaction abort,

15 . The computer program product of claim 14 , further comprising:
eighth program instructions programmed to complete the current transaction; and ninth program instructions programmed to provide a response to the request when the current transaction has completed.

16 . The computer program product of claim 14 , further comprising:
eighth program instructions programmed to determine a possibility of a deadlock; and ninth program instructions programmed to abort the current transaction based on the possibility of a deadlock.

17 . A computer system for enabling end of transaction detection using speculative look ahead, the computer system comprising:
a processor set; and a computer readable storage medium; wherein: the processor set is structured, located, connected and/or programmed to run program instructions stored on the computer readable storage medium; and the program instructions include:
first program instructions programmed to set an indicator to indicate a current transaction is being processed;
second program instructions programmed to monitor a speculative look ahead operation to detect whether an end-transaction instruction corresponding to the current transaction is likely to occur; and
third program instructions programmed to, responsive to detecting the end-transaction instruction, enable a near-end-transaction processing mode.

18 . The computer system of claim 17 , further comprising:
fourth program instructions programmed to receive a notification of an interference corresponding to the current transaction and a second computer process; and fifth program instructions programmed to determine an interference action; wherein: the notification of the interference further includes an abort request for the current transaction.

19 . The computer system of claim 18 , wherein the interference action includes:
sixth program instructions programmed to, responsive to a request for a memory location, defer a response to the request based on the indicating the end-transaction has been detected; and seventh program instructions programmed to, responsive to the notification of an interference, defer the abort of the current transaction.

20 . The computer system of claim 18 , further comprising:
eighth program instructions programmed to complete the current transaction; and ninth program instructions programmed to provide a response to the request when the current transaction has completed.

Assignees

• IBM

Inventors

• Gschwind Michael Karl
• Michael Maged M
• Salapura Valentina

Classifications

• G06F9/3004 Primary

  to perform operations on memory · CPC title

• G06F9/466

  Transaction processing · CPC title

• G06F9/3842 Primary

  Speculative instruction execution · CPC title

• D10B2321/0211

  high-strength or high-molecular-weight polyethylene, e.g. ultra-high molecular weight polyethylene [UHMWPE] · CPC title

• D02G3/32

  Elastic yarns or threads {; Production of plied or cored yarns, one of which is elastic} · CPC title