Method and apparatus for modular reordering of portions of a computer program based on profile data

• US 6,029,004 A
• Filed: 03/17/1997
• Issued: 02/22/2000
• Est. Priority Date: 03/17/1997
• Status: Expired due to Fees

• Current Assignee: International Business Machines Corporation
• Original Assignee: International Business Machines Corporation
• Inventors: Novick, Mark, Bortnikov, Vita, Schmidt, William Jon, Roediger, Robert Ralph, Mendelson, Bilha, Shavit-Lottem, Inbal
• Primary Examiner(s): Trammell, James P.
• Assistant Examiner(s): Dam, Tuan Q.
• Application Number:
  US08/819,526
• Time in Patent Office: 1,072 Days
• Field of Search: 395/709, 395/704, 395/705, 395/183.14, 395/183.01, 395/390, 395/392, 395/380, 395/588, 395/580, 714/38, 714/37, 714/35, 712/214, 712/226, 712/227, 712/241, 712/233, 712/234, 712/216, 712/204
• US Class Current: 717/158
• CPC Class Codes: G06F 8/445 Exploiting fine grain parallelism, i.e. parallelism at instruction level run-time instruction scheduling G06F9/3836

Abstract

An apparatus and method reorder portions of a computer program in a way that achieves both enhanced performance and maintainability of the computer program. A global call graph is initially constructed that includes profile data. From the information in the global call graph, an intramodular call graph is generated for each module. Reordering techniques are used to reorder the procedures in each module according to the profile data in each intramodular call graph. An intermodular call graph is generated from the information in the global call graph. Reordering techniques are used to reorder the modules in the computer program. By reordering procedures within modules, then reordering the modules, enhanced performance is achieved without reordering procedures across module boundaries. Respecting module boundaries enhances the maintainability of the computer program by allowing a module to be replaced without adversely affecting the other modules while still providing many of the advantages of global procedure reordering.

Claims

1. An apparatus comprising:

at least one processor;

a memory coupled to the at least one processor;

a computer program residing in the memory, the computer program including at least one procedure within each of a plurality of modules;

profile data residing in the memory that represents the execution frequency of at least one procedure within at least one of the plurality of modules in the computer program;

a reordering mechanism residing in the memory and executed by the at least one processor, the reordering mechanism reordering a plurality of procedures within at least one of the plurality of modules based on a portion of the profile data corresponding to the plurality of procedures and reordering the plurality of modules based on a portion of the profile data corresponding to procedures within the plurality of modules.

2. The apparatus of claim 1 wherein the profile data comprises a global call graph for the computer program.

3. The apparatus of claim 1 wherein the reordering mechanism comprises a call graph partitioner for generating at least one intramodular call graph from the profile data and for generating at least one intermodular call graph from the profile data.

4. The apparatus of claim 3 wherein the reordering mechanism comprises a procedure reordering mechanism that reorders the plurality of procedures within a selected one of the plurality of modules based on the profile data in the intramodular call graph that corresponds to the selected module.

5. The apparatus of claim 3 wherein the reordering mechanism comprises a module reordering mechanism that reorders the plurality of modules based on the profile data in the intermodular call graph.

6. An apparatus comprising:

at least one processor;

a memory coupled to the at least one processor;

a computer program residing in the memory, the computer program including at least one procedure within each of a plurality of modules;

profile data residing in the memory that represents the execution frequency of at least one procedure within at least one of the plurality of modules in the computer program;

a reordering mechanism residing in the memory and executed by the at least one processor, the reordering mechanism generating an intramodular call graph from the profile data for a selected one of the plurality of modules in the computer program and reordering the procedures within the selected module based on the profile data within the intramodular call graph.

7. The apparatus of claim 6 wherein the profile data comprises a global call graph for the computer program.

8. The apparatus of claim 6 wherein the reordering mechanism further generates an intermodular call graph from the profile data and reorders the plurality of modules based on the profile data within the intermodular call graph.

9. An apparatus comprising:

at least one processor;

a memory coupled to the at least one processor;

a computer program residing in the memory, the computer program including at least one procedure within each of a plurality of modules;

profile data residing in the memory that represents the execution frequency of at least one procedure within at least one of the plurality of modules in the computer program;

a reordering mechanism residing in the memory and executed by the at least one processor, the reordering mechanism generating an intermodular call graph from the profile data and reordering the plurality of modules based on the profile data within the intermodular call graph.

10. The apparatus of claim 9 wherein the profile data comprises a global call graph for the computer program.

11. An apparatus comprising:

at least one processor;

a memory coupled to the at least one processor;

a computer program residing in the memory, the computer program including at least one procedure within each of a plurality of modules;

a global call graph residing in the memory that represents the execution frequency of a plurality of procedures within at least one of the plurality of modules in the computer program;

a reordering mechanism residing in the memory and executed by the at least one processor, the reordering mechanism comprising;

a call graph partitioner, the call graph partitioner generating an intramodular call graph and an intermodular call graph from the global call graph;

a procedure reordering mechanism, the procedure reordering mechanism reordering the plurality of procedures within a selected one of the plurality of modules based on profile data in the intramodular call graph that corresponds to the selected module; and

a module reordering mechanism, the module reordering mechanism reordering the plurality of modules based on profile data within the intermodular call graph.

12. A method for improving execution speed of a computer program on a computer apparatus by reordering procedures and modules in the computer program according to profile data that represents the execution frequency of at least one procedure within at least one of a plurality of modules in the computer program, the computer program including at least one procedure within each of the plurality of modules, the method comprising the steps of:

reordering a plurality of procedures within at least one of the plurality of modules based on a portion of the profile data corresponding to the plurality of procedures; and

reordering the plurality of modules based on a portion of the profile data corresponding to procedures within the plurality of modules.

13. The method of claim 12 wherein the step of reordering the plurality of procedures within at least one of the plurality of modules comprises the steps of:

generating an intramodular call graph from the profile data for a selected one of the plurality of modules in the computer program; and

reordering the procedures within the selected module based on the profile data within the intramodular call graph.

14. The method of claim 13 wherein the step of generating the intramodular call graph comprises the steps of:

generating a global call graph for the computer program from the profile data, the global call graph containing the plurality of modules that each contain at least one procedure; and

removing arcs in the global call graph that cross the boundaries of the selected module.

15. The method of claim 12 wherein the step of reordering the plurality of modules comprises the steps of:

generating an intermodular call graph from the profile data; and

reordering the plurality of modules based on the profile data within the intermodular call graph.

16. The method of claim 15 wherein the step of generating the intermodular call graph comprises the steps of:

generating a global call graph for the computer program from the profile data, the global call graph containing the plurality of modules that each contain at least one procedure;

removing the procedures within the modules of the global call graph;

retaining the arcs between modules; and

combining multiple arcs that span from a first module to a second module into a single arc with a weight equal to the sum of the weights of the multiple arcs.

17. The method of claim 12 further comprising the step of generating a global call graph from the profile data.

18. A method for improving execution speed of a computer program on a computer apparatus by reordering procedures in the computer program according to profile data that represents the execution frequency of at least one procedure within at least one of a plurality of modules in the computer program, the computer program including at least one procedure within each of the plurality of modules, the method comprising the steps of:

generating an intramodular call graph from the profile data for a selected one of the plurality of modules in the computer program; and

reordering the procedures within the selected module based on the profile data within the intramodular call graph.

19. The method of claim 18 wherein the step of generating the intramodular call graph comprises the steps of:

generating a global call graph for the computer program from the profile data, the global call graph containing the plurality of modules that each contain at least one procedure; and

removing arcs in the global call graph that cross the boundaries of the selected module.

20. The method of claim 18 further comprising the steps of:

generating an intermodular call graph from the profile data; and

reordering the plurality of modules based on the profile data within the intermodular call graph.

21. The method of claim 20 wherein the step of generating the intermodular call graph comprises the steps of:

generating a global call graph for the computer program from the profile data, the global call graph containing the plurality of modules that each contain at least one procedure;

removing the procedures within the modules of the global call graph;

retaining the arcs between modules; and

combining multiple arcs that span from a first module to a second module into a single arc with a weight equal to the sum of the weights of the multiple arcs.

22. The method of claim 18 further comprising the step of generating a global call graph from the profile data.

23. A method for improving execution speed of a computer program on a computer apparatus by reordering procedures in the computer program according to profile data that represents the execution frequency of at least one procedure within at least one of a plurality of modules in the computer program, the computer program including at least one procedure within each of the plurality of modules, the method comprising the steps of:

generating an intermodular call graph from the profile data; and

reordering the plurality of modules based on the profile data within the intermodular call graph.

24. The method of claim 23 wherein the step of generating the intermodular call graph comprises the steps of:

generating a global call graph for the computer program from the profile data, the global call graph containing the plurality of modules that each contain at least one procedure;

removing the procedures within the modules of the global call graph;

retaining the arcs between modules; and

combining multiple arcs that span from a first module to a second module into a single arc with a weight equal to the sum of the weights of the multiple arcs.

25. The method of claim 23 further comprising the step of generating a global call graph from the profile data.

26. A method for improving execution speed of a computer program on a computer apparatus by reordering procedures and modules in the computer program according to profile data, the computer program including at least one procedure within each of the plurality of modules, the method comprising the steps of:

generating a global call graph for the computer program from the profile data;

generating an intramodular call graph from the global call graph for each of the plurality of modules in the computer program;

reordering the procedures within each of the plurality of modules based on profile data within the corresponding intramodular call graph;

generating an intermodular call graph from the global call graph; and

reordering the plurality of modules based on profile data within the intermodular call graph.

27. A program product comprising:

(A) a reordering mechanism that reorders a plurality of procedures within at least one of a plurality of modules in a computer program based on profile data corresponding to the plurality of procedures and that reorders the plurality of modules based on profile data corresponding to procedures within the plurality of modules; and

(B) signal bearing media bearing the reordering mechanism.

28. The program product of claim 27 wherein the signal bearing media comprises recordable media.

29. The program product of claim 27 wherein the signal bearing media comprises transmission media.

30. The program product of claim 27 wherein the profile data comprises a global call graph for the computer program.

31. The program product of claim 27 wherein the reordering mechanism comprises a call graph partitioner for generating at least one intramodular call graph from the profile data and for generating at least one intermodular call graph from the profile data.

32. The program product of claim 31 wherein the reordering mechanism comprises a procedure reordering mechanism that reorders the plurality of procedures within a selected one of the plurality of modules based on the profile data in the intramodular call graph that corresponds to the selected module.

33. The program product of claim 31 wherein the reordering mechanism comprises a module reordering mechanism that reorders the plurality of modules based on the profile data in the intermodular call graph.

34. A program product comprising:

(A) a reordering mechanism that generates an intramodular call graph from profile data for a selected one of the plurality of modules in a computer program and that reorders the procedures within the selected module based on the profile data within the intramodular call graph; and

(B) signal bearing media bearing the reordering mechanism.

35. The program product of claim 34 wherein the signal bearing media comprises recordable media.

36. The program product of claim 34 wherein the signal bearing media comprises transmission media.

37. The program product of claim 34 wherein the profile data comprises a global call graph for the computer program.

38. The program product of claim 34 wherein the reordering mechanism generates an intermodular call graph from the profile data and reorders the plurality of modules based on the profile data within the intermodular call graph.

39. A program product comprising:

(A) a reordering mechanism for generating an intermodular call graph from profile data relating to a computer program, the reordering mechanism reordering a plurality of modules within a computer program based on the profile data within the intermodular call graph; and

(B) signal bearing media bearing the reordering mechanism.

40. The program product of claim 39 wherein the signal bearing media comprises recordable media.

41. The program product of claim 39 wherein the signal bearing media comprises transmission media.

42. The apparatus of claim 39 wherein the profile data comprises a global call graph for the computer program.