You can verify this using a system tool like HP GlancePlus. The possible remedies for thrashing:
•Decrease the maximum heap size, which corresponds to a decrease of the maximum load supported by the application.
•Eliminate other load on the system.•Install more physical memory.Related Topics
•Garbage Collections (page 123)
•Heap Usage Notification (page 111)
Identifying Excessive Calls to System.gc()
Use the Heap Monitor display.
When a high level of detail is selected (1 to 20 minutes), this metric can help detect if calls to System.gc() are creating a performance problem. When your application calls this method, you see that the heap size does not go to the local maximum before a garbage collection happens. However, from time to time, the JVM may automatically invoke garbage collection in such circumstance, too.
A rule of thumb is that if over half of all garbage collections seem to happen when the heap is not full, then it may mean explicit calls to System.gc() are occurring. Remove explicit calls from your application, either by modifying the code or by using an appropriate JVM option.
These calls rarely improve the overall performance of the application.Related Topics
•Garbage Collections (page 123)
•Heap Usage Notification (page 111)
•Using Specialized Garbage Collection Displays (page 157)
Reviewing the Percentage of Time Spent in Garbage Collection
The percentage of time your application spends in garbage collection can help you identify potential problems. Use the % Time Spent in Garbage Collection display to view this information. For details, see Percentage of Time Spent in Garbage Collection (page 125).
In this example, you see a fairly normal application behavior.•A low flat graph•A low average value, represented by the red lineDiagnosing Errors When Monitoring Running Applications | 41 |