menu bar. HPjmeter automatically recalculates the call count for each method in the peak data with the result that each value is normalized to the ratio of the call counts for the selected method.
HPjmeter then sorts the data. By viewing the information that appears in the newly sorted list, you can compare differences in activity between the two data files. If you want to see how this works in detail, select View→Show Formula to display the calculations that HPjmeter uses.
Reading Profiling Histograms
There are two kinds of histograms available:•Threads Histogram. A presentation of all threads created by the application.The horizontal bars represent the lifetime of the threads, with respect to the lifetime of the whole application.
•Thread Groups Histogram. A presentation of all thread groups created by the application.
The horizontal bars represent the lifetime of the thread groups, with respect to the lifetime of the whole application. The lifetime of the thread group is defined as the time span between the creation of the first thread belonging to the group and the death of the last thread belonging to the group.
Not all profile data files contain information about the times when the threads are created and terminated. If such information is unavailable, the metric header will contain “times not to scale)” meaning that only the order of the threads creation and termination events are shown.
If the profile data contains adequate information, the bars are displayed using colors describing thread states; otherwise the bars are gray. There are a few coloring schemas used by HPjmeter, depending on the profiling option and platform used. You can double click on the thread (or thread group) bar to pop up the thread spectrum.
The next section presents a detailed description of the reported thread states.Key to Thread States Reported by
The image in the next figure presents a sample thread spectrum. A thread spectrum is obtained when you
Figure
The values are shown as the percentage of the total thread lifetime (i.e., the clock time elapsed between the thread creation and the thread completion).
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