Modifying code to reduce redundant or unnecessary power usage

• US 10,133,557 B1
• Filed: 01/13/2014
• Issued: 11/20/2018
• Est. Priority Date: 01/11/2013
• Status: Active Grant

• Current Assignee: Siemens Industry Software Limited (Siemens AG)
• Original Assignee: Mentor Graphics Corporation (Siemens AG)
• Inventors: Tripathi, Nikhil, Yechangunja, Srihari, Kumar, Mohit
• Primary Examiner(s): Rivera, Anibal
• Application Number:
  US14/154,029
• Time in Patent Office: 1,772 Days
• CPC Class Codes: G06F 1/329 by task scheduling
• CPC Class Codes: G06F 11/3447 Performance evaluation by modeling
• CPC Class Codes: G06F 11/3608 using formal methods, e.g. model checking, abstract interpretation theorem proving G06N5/013
• CPC Class Codes: G06F 11/366 using diagnostics G06F11/0703 takes precedence
• CPC Class Codes: G06F 11/3688 for test execution, e.g. scheduling of test suites
• CPC Class Codes: G06F 8/30 Creation or generation of source code
• CPC Class Codes: G06F 8/41 Compilation
• CPC Class Codes: G06F 8/75 Structural analysis for program understanding
• CPC Class Codes: Y02D 10/00 Energy efficient computing, e.g. low power processors, power management or thermal management
• CPC Class Codes: Y02D 30/50 in wire-line communication networks, e.g. low power modes or reduced link rate

Abstract

Disclosed herein are representative embodiments of methods, apparatus, and systems for analyzing and/or transforming code (typically, source code) to reduce or avoid redundant or unnecessary power usage (e.g., power cycling, resource leak bugs, and/or unnecessarily repeated activity) in the device that will ultimately execute the application defined by the source code. The disclosed methods can be implemented by a software tool (e.g., a static program analysis tool or EDA analysis tool) that analyzes and/or transforms source code for a software application to help improve the performance of the software application on the target device. The disclosed methods, apparatus, and systems should not be construed as limiting in any way.

Claims

1. A computer-implemented method for reducing power usage of a device, comprising:

inputting, by computing hardware, original source code for an application;

analyzing a situation where batching is possible by identifying, from one or more instruction sequences of the original source code, library function calls that corresponds to radio requests;

estimating a power gain from batching together two or more portions of the original source code library function calls that request operation of one or more power-consuming hardware components, wherein the estimating comprises computing a minimum or average time period between execution of the two or more of the portions of the original source code library function calls, analyzing power state transitions of the radio request, and comparing the cost of the power state transitions with savings due to idle inactivity time of the power-consuming hardware components; and

modifying, by the computing hardware, the original source code so that the two or more portions of the original source code are batched together removing instances of redundant power cycling, thereby creating modified source code from which the one or more power-consuming hardware components are operated in a more power efficient manner.

2. The computer-implemented method of claim 1, wherein the modifying reduce redundant power cycling from the original source code.

3. The computer-implemented method of claim 1, further comprising generating and analyzing a data flow graph representative of the original source code.

4. The computer-implemented method of claim 3, further comprising restructuring the data flow graph.

5. The computer-implemented method of claim 4, wherein the modifying further comprises modifying affected lines of the original source code based on the restructured data flow graph.

6. The computer-implemented method of claim 1, wherein the estimating comprises constructing a finite state machine that represents various power states of the power-consuming hardware components and estimating power for each of the various power states.

7. The computer-implemented method of claim 1, wherein the original source code is for an application to be executed on a mobile device, and wherein the one or more power-consuming hardware components comprise a radio transceiver of the mobile device.

8. The computer-implemented method of claim 1, wherein the modified source code is associated with a number of power cycles that is lower than a number of power cycles performed by the one or more power-consuming hardware components when operating under the original source code.

9. One or more non-transitory computer-readable media storing computer-executable instructions which when executed by a computer cause the computer to perform the method of claim 1.

10. A computer-implemented method comprising:

inputting, by computing hardware, original source code for an application that requests operation of one or more power-consuming hardware components;

analyzing, by the computing hardware, the original source code to identify portions of the original source code that request operation of a power-consuming resource for a task but fail to release the power-consuming resource after the task is completed, wherein the analyzing comprises;

identifying a first union of multiple conditions specified in the original source code upon which the power-consuming resource is acquired;

identifying a second union of multiple conditions specified in the original source code upon which the power-consuming resource is released; and

evaluating a set difference between the first union and the second union, to determine as a resource leak one or more conditions upon which the power-consuming resource is acquired but not released; and

modifying, by the computing hardware, the original source code by inserting a code portion that releases the power-consuming resource after the task is completed.

11. The computer-implemented method of claim 10, wherein the analyzing and modifying reduces resource leaks caused by the original source code.

12. The computer-implemented method of claim 10, wherein the analyzing comprises:

generating a data flow graph representative of the original source code; and

analyzing branches of the data flow graph to identify one or more unreleased power-consuming resources.

13. The computer-implemented method of claim 12, wherein the modifying comprises inserting the code portion that releases the power-consuming resource at a location of the original source code corresponding to a common exit point for two or more branches of the data flow graph, where the two or more branches are identified as having a common unreleased power-consuming resource.

14. The computer-implemented method of claim 12, wherein the modifying comprises restructuring the data flow graph.

15. The computer-implemented method of claim 14, wherein the modifying further comprises modifying affected lines of the original source code based on the restructured data flow graph.

16. The computer-implemented method of claim 10, further comprising iteratively performing, by the computing hardware, the analyzing and modifying as each instance of an unreleased power-consuming resource is identified.

17. The method of claim 10, wherein the application is an application for a smart phone or tablet computer, and wherein the power-consuming resource that is released by the code portion after the task is completed is a transceiver or touch screen of the smart phone or tablet computer.

18. One or more non-transitory computer-readable media storing computer-executable instructions which when executed by a computer cause the computer to perform the method of claim 10.

19. A computer-implemented method comprising:

inputting, by computing hardware, original source code for an application that invokes operation of one or more power-consuming components;

analyzing, by the computing hardware, the original source code to identify an instance of a stability redundancy in the original source code, the stability redundancy causing unnecessary processing to be performed during execution of two successive calls to a program object because one or more variables or values acted on by the two successive calls to the program object remain stable between the two successive calls; and

modifying, by the computing hardware, the original source code to reduce the amount of unnecessary processing performed during the execution of the two successive calls to the program object,

wherein the modifying comprises, subsequent to the analyzing, inserting one or more code segments into the original source code that create a tracking variable or tracking flag that tracks at runtime whether a respective one of the variables or values has been updated.

20. The method of claim 19, wherein the two successive calls invoke operation of a respective one of the power-consuming components.

21. The method of claim 20, wherein the original source code is for an application to be executed on a smart phone or tablet computer, and wherein the respective one of the power-consuming components is a touch screen or radio transceiver of the smart phone or tablet computer.

22. The method of claim 19, wherein the analyzing comprises:

unrolling loops from the source code that represents the two successive calls to the program object;

inlining the unrolled loops; and

identifying instances of redundant processing from the inlined source code.

23. The method of claim 19, wherein the modifying further comprises inserting code segments into the original source code that bypass one or more operations from the original source code based on the tracking variable or tracking flag.

24. The method of claim 19, wherein the method further comprises:

prior to the modifying and by the computing hardware, evaluating a memory cost of the modifying; and

performing the modifying by the computing hardware if the memory cost satisfies a memory cost threshold.

25. One or more non-transitory computer-readable media storing computer-executable instructions which when executed by a computer cause the computer to perform the method of claim 19.