Cache monitoring using shared memory

• US 20060248276A1
• Filed: 04/28/2005
• Published: 11/02/2006
• Est. Priority Date: 04/28/2005
• Status: Active Grant

• Current Assignee: SAP SE
• Original Assignee: SAP AG (SAP SE)
• Inventors: Kilian, Frank, Petev, Petio, Fleischer, Christian
• Granted Patent: US 7,516,277 B2
• Time in Patent Office: Days
• US Class Current: 711/130
• CPC Class Codes: G06F 12/0831 using a bus scheme, e.g. with bus monitoring or watching means
• CPC Class Codes: G06F 12/084 with a shared cache
• CPC Class Codes: G06F 12/0842 for multiprocessing or multitasking

Abstract

A system and method to monitor caches of at least one Java virtual machine (“JVM”). A program is operated on the at least one JVM. Objects associated with the program are cached within a local cache of the JVM. Cache status information about the local cache is generated and then the cache status information is reported into memory external to the JVM to enable monitoring of the local cache from external to the JVM.

Claims

1. A method, comprising:

operating a program on a Java virtual machine (“

JVM”

);

caching objects associated with the program within a local cache;

generating cache status information about the local cache; and

exporting the cache status information into memory external to the JVM during operation of the program.

2. The method of claim 1, further comprising:

performing an operation on the local cache; and

updating the cache status information in the memory external to the JVM in response to performing the operation to enable event based real-time monitoring of the local cache from external to the JVM during operation of the program.

3. The method of claim 2, wherein performing the operation on the local cache comprises performing at least one of a PUT, a GET, a REMOVAL, or an EVICTION operation on the local cache and wherein updating the status information comprises updating at least one of a PUT COUNT, a GET COUNT, a REMOVAL COUNT, or an EVICTION COUNT maintained in the memory external to the JVM.

4. The method of claim 2, wherein the JVM is operated within an application server (“

AS”

) instance, and further comprising;

receiving a request for the cache status information;

retrieving the cache status information from the memory external to the JVM; and

transmitting the cache status information to a monitoring console to display the cache status information, the monitoring console being external to the AS instance.

5. The method of claim 1, further comprising:

operating multiple programs within multiple JVMs of an application server (“

AS”

) instance;

caching objects associated with each of the multiple programs within corresponding multiple local caches;

generating cache status information about each of the multiple local caches; and

reporting the cache status information for each of the multiple local caches into shared memory external to the multiple JVMs to enable monitoring of each of the multiple local caches from external to the multiple JVMs.

6. The method of claim 5, further comprising:

registering reporting slots within the shared memory, each one of the reporting slots corresponding to one of the multiple local caches; and

reporting the cache status information for each of the multiple local caches into a corresponding one of the reporting slots.

7. The method of claim 6, wherein each of the reporting slots includes a cache monitoring table to store the cache status information corresponding to one of the local caches, the cache status information including at least a total size of the objects cached within the one of the local caches, a total number of the objects cached within the one of the local caches, and cache utilization statistics.

8. The method of claim 6, further comprising:

caching shared objects accessible by two or more of the applications within a shared cache;

generating shared cache status information about the shared cache; and

reporting the shared cache status information into the shared memory in response to an operation performed on one of the shared objects.

9. The method of claim 1, wherein the program comprises a Java program operating on the JVM and wherein the local cache comprises a local cache internal to the JVM and created for the Java program.

10. A machine-accessible medium that provides instructions that, if executed by a machine, will cause the machine to perform operations comprising:

operating Java programs within multiple Java virtual machines (“

JVMs”

) of an application server (“

AS”

) instance;

caching objects associated with each of the Java programs within corresponding local caches;

generating cache status information about each of the local caches; and

exporting the cache status information for each of the local caches into shared memory external to the multiple JVMs.

11. The machine-accessible medium of claim 10, further providing instructions that, if executed by the machine, will cause the machine to perform further operations, comprising:

performing an operations on one of the local caches; and

updating the cache status information corresponding to the one of the local caches in the shared memory external to the multiple JVMs in response to performing the operation to enable event based monitoring of the one of the local caches from external to the multiple JVMs during operation of the JVMs.

12. The machine-accessible medium of claim 11, further providing instructions that, if executed by the machine, will cause the machine to perform further operations, comprising:

receiving a request for the cache status information;

retrieving the cache status information from the shared memory; and

transmitting the cache status information to a remote monitoring console to display the cache status information, the remote monitoring console being external to the AS instance.

13. The machine-accessible medium of claim 10, further providing instructions that, if executed by the machine, will cause the machine to perform further operations, comprising:

registering reporting slots within the shared memory, each one of the reporting slots corresponding to one of the local caches; and

reporting the cache status information for each of the local caches into a corresponding one of the reporting slots.

14. The machine-accessible medium of claim 13, wherein each of the reporting slots includes a cache monitoring table to store the cache status information corresponding to one of the local caches, the cache status information including at least a total size of the objects cached within the one of the local caches, a total number of the objects cached within the one of the local caches, and cache utilization statistics.

15. The machine-accessible medium of claim 13, further providing instructions that, if executed by the machine, will cause the machine to perform further operations, comprising:

caching shared objects accessible by two or more of the Java applications within a shared cache, the two or more Java applications operating within different JVMs of the AS instance;

generating shared cache status information about the shared cache; and

reporting the shared cache status information into the shared memory in response to an operation performed on one of the shared objects.

16. A system, comprising:

a Java virtual machine (“

JVM”

) to operate Java programs, the JVM including;

local caches each to cache objects associated with one of the Java programs; and

a cache manager to collect cache status information about the local caches and to export the cache status information external to the JVM during operation of the JVM; and

a memory buffer external to the JVM to store the cache status information collected by the cache manager.

17. The system of claim 16, further comprising:

a network interface communicatively coupled to the monitoring console, the network interface further configured to access the memory buffer and to retrieve the cache status information therefrom; and

a monitoring console communicatively coupled to the network interface to receive the cache status information from the network interface and to display the cache status information.

18. The system of claim 17, further comprising a plurality of JVMs grouped into an application server (“

AS”

) instance, and wherein the memory buffer comprises a shared memory including reporting slots, each reporting slot to store cache status information associated with caches of each of the plurality of JVMs and received in real-time from each of the plurality of JVMs.

19. The system of claim 16, wherein the cache manager is configured to report the cache status information into the memory buffer in response to at least one of a PUT, a GET, a REMOVAL, or an EVICTION operation performed on one of the local caches.

20. The system of claim 19, wherein the cache status information includes at least a total size of the objects cached within each of the local caches, a total number of the objects cached within each of the local caches, and cache utilization statistics of each of the local caches.