Figure 8-8 Monitoring Metric: Allocated Object Statistics by Class

Related Topics

•Identifying Excessive Object Allocation (page 44)

•JVM Agent Options (page 17)

•“Data Sampling Considerations”

•Mark an Item for Search (page 178)

•Find a Search Pattern (page 179)

Allocating Method StatisticsShows the methods that allocate the most objects.

This metric is useful when you choose to decrease heap pressure by modifying the application code.

Guidelines

Methods listed at the top should become the primary candidates for optimization.

Details

For those classes that are instrumented (visible through the JVM agent verbose flag), every object allocation in every method is instrumented to report allocations. However, sampling is used to minimize overhead, so the metric reports allocation percentages, not total allocation counts.

These percentages are not absolute across the entire application, but are computed with respect to allocations in instrumented classes.

Sampling minimizes overhead and focuses attention on user code. To discover allocation statistics about application server classes, use the include and exclude filtering flags in the JVM agent options.

The reported data is cumulative over the lifetime of the session, and accuracy will improve as the session length increases.

128 Using Visualizer Functions