Asynchronous dynamic compilation based on multi-session profiling to produce shared native code

• US 8,413,125 B2
• Filed: 01/26/2007
• Issued: 04/02/2013
• Est. Priority Date: 01/26/2007
• Status: Active Grant

• Current Assignee: Oracle International Corporation (Oracle Corporation)
• Original Assignee: Oracle International Corporation (Oracle Corporation)
• Inventors: Lee, Robert H., Unietis, David, Jungerman, Mark
• Primary Examiner(s): Zhen, Wei
• Assistant Examiner(s): BROPHY, MATTHEW J
• Application Number:
  US11/698,629
• Publication Number:
  US 20080184210A1
• Time in Patent Office: 2,258 Days
• Field of Search: 717/139, 717/148
• US Class Current: 717/148
• CPC Class Codes: G06F 8/4434 Reducing the memory space required by the program code
• CPC Class Codes: G06F 8/4441 Reducing the execution time required by the program code
• CPC Class Codes: G06F 9/4484 Executing subprograms
• CPC Class Codes: G06F 9/45525 Optimisation or modification within the same instruction set architecture, e.g. HP Dynamo
• CPC Class Codes: G06F 9/544 Buffers; Shared memory; Pipes

Abstract

A computer is programmed to automatically have multiple sessions update a common counter which is shared therebetween, when interpreting a given method so that system-wide statistics are collected for each method. The single counter is commonly accessed for updating by the respective interpreters in the multiple sessions which are executing the method. The computer is further programmed to asynchronously compile the method (regardless of the state of the multiple sessions), to obtain compiled software in the form of executable machine instructions. Specifically, asynchronous compilation starts dynamically, whenever a method'"'"'s common multi-session counter satisfies a predetermined condition. Finally, each session is informed when compilation is completed so that the next time the method needs to be run, it is not interpreted and instead the compiled software is executed. The compiled software is kept in a shared memory which is accessible to each session.

Claims

1. A computer-implemented method of creating machine instructions, the method comprising:

each session in a plurality of sessions updating a multi-session counter in response to an interpreter executing within said each session, a given method comprising a plurality of to-be-interpreted instructions;

wherein the multi-session counter is updated by multiple sessions concurrently or simultaneously without locking, wherein in the event that one session starts updating the multi-session counter before another session finishes updating the multi-session counter, the multi-session counter becomes inaccurate relative to a number of interpretations of the given method in the plurality of sessions;

a common process for the plurality of sessions compiling the given method to obtain compiled software, in response to the multi-session counter exceeding a preset limit, regardless of whether the multi-session counter has become inaccurate; and

after completion of the compiling, said each session executing the compiled software from a shared memory accessible to the plurality of sessions.

2. The computer-implemented method of claim 1 wherein:

the compiling is performed in a just-in-time manner in response to the predetermined condition being met.

3. The computer-implemented method of claim 1 wherein each session uses a private memory comprising:

a flag indicating presence or absence of the compiled software; and

a pointer initialized to the compiled software in the shared memory when the flag indicates presence.

6. The computer-implemented method of claim 1 wherein:

the plurality of to-be-interpreted instructions comprises a loop.

7. The computer-implemented method of claim 6 wherein:

the multi-session counter is incremented on every iteration through the loop, without regard to session boundaries.

8. The computer-implemented method of claim 1 wherein:

the given method has a name, multiple argument types and multiple return types.

9. The computer-implemented method of claim 1 wherein:

the compiled software is comprised in a code bundle; and

the code bundle comprises information to transfer control across page boundaries.

20. The apparatus of claim 6 wherein:

the predetermined software has a name, multiple argument types and multiple return types.

4. A non-transitory computer-readable storage medium comprising a plurality of instructions, the plurality of instructions comprising:

instructions to each session in a plurality of sessions to update a multi-session counter in response to an interpreter executing within said each session, a given method comprising a plurality of to-be-interpreted instructions;

wherein on execution of the instructions, the multi-session counter is updated by multiple sessions concurrently or simultaneously without locking, wherein in the event that one session starts updating the multi-session counter before another session finishes updating the multi-session counter, the multi-session counter becomes inaccurate relative to a number of interpretations of the given method in the plurality of sessions;

instructions to a common process compiling the given method to obtain compiled software, in response to the multi-session counter exceeding a preset limit, regardless of whether the multi-session counter has become inaccurate; and

instructions to said each session to execute the compiled software from a shared memory accessible to the plurality of sessions, after completion of compiling by the common process.

10. The non-transitory computer-readable storage medium of claim 4 wherein:

the plurality of to-be-interpreted instructions comprises a loop.

11. The non-transitory computer-readable storage medium of claim 10 wherein:

the multi-session counter is incremented, during execution of said plurality of to-be-interpreted instructions, on every iteration through the loop, without regard to session boundaries.

12. The non-transitory computer-readable storage medium of claim 4 wherein:

the given method has a name, multiple argument types and multiple return types.

13. The non-transitory computer-readable storage medium of claim 4 wherein:

the compiled software is comprised in a code bundle; and

the code bundle comprises information to transfer control across page boundaries.

14. The non-transitory computer-readable storage medium of claim 4 further comprising:

instructions to each session to use a private memory comprising a flag indicating presence or absence of the compiled software and a pointer initialized to the compiled software in the shared memory when the flag indicates presence.

15. The non-transitory computer-readable storage medium of claim 4 wherein:

the instructions to the common process are to perform the compiling in a just-in-time manner in response to the predetermined condition being met.

5. An apparatus for creating and executing machine instructions, the apparatus comprising:

means for each session in a plurality of sessions for updating a multi-session counter in response to an interpreter executing a predetermined software within said each session;

wherein the multi-session counter is updated by the means of multiple sessions concurrently or simultaneously without locking, wherein in the event that the means of one session starts updating the multi-session counter before the means of another session finishes updating the multi-session counter, the multi-session counter becomes inaccurate relative to a number of interpretations of the predetermined software in the plurality of sessions;

means for a common process for compiling the predetermined software to obtain compiled software comprising machine instructions, in response to the multi-session counter exceeding a preset limit, regardless of whether the multi-session counter has become inaccurate; and

means for said each session for executing the compiled software from a shared memory accessible to the plurality of sessions, after completion of compiling by the common process.

16. The apparatus of claim 5 wherein:

the means for compiling uses the common process to perform the compiling in a just-in-time manner in response to the predetermined condition being met.

17. The apparatus of claim 5 wherein:

the compiled software is comprised in a code bundle; and

the code bundle comprises information to transfer control across page boundaries.

18. The apparatus of claim 5 wherein each session uses a private memory comprising:

a flag indicating presence or absence of the compiled software; and

a pointer initialized to the compiled software in the shared memory when said flag indicates presence.

19. The apparatus of claim 5 wherein:

the predetermined software comprises a loop; and

the multi-session counter is incremented on every iteration through the loop, without regard to session boundaries.