Views within the WebSphere Real Time perspective
Each view within the WebSphere® Real Time perspective presents data in specific sections of the display.
The Controller window
- Manage custom views
- You can create a customized view, and add it to the list of available views. For more information about creating customized views, see Customizing the WebSphere Real Time perspective.
- Select different views
- You can select different views, by using a combination box. The box is populated initially with predefined views. Customized views also appear in this box if a custom view definition file has been created and identified in the preferences.
All predefined views are identified by a System view: prefix. All customized views are identified by a Custom view: prefix.
The Plot window
This window displays event data as a simple plot graph. The X-axis of the graph shows the actual time when an event took place. The Y-axis shows the time taken for the event to occur. For convenience, the Y-axis values can be adjusted to display with a logarithmic scale.
Use the Threads window to control which threads are visible on the graph, and the color that is used to display each thread.
When you hover over data in the plot window, a window opens providing details of the trace point associated with the event.
A number of outlier events are highlighted by numbered circles on the graph. The number of outliers that is displayed is determined by the Number of outliers to analyze setting in the WebSphere Real Time preferences. Events are shown as highlighted outliers only if they fall outside the range of events that are used for the determinism score calculation. In other words, if the events take longer than twice the median value.
- The thread was delayed because of class loading.
- The thread was delayed because all the available processors were busy with other threads, or if you are using WebSphere Real Time for RT Linux, higher priority threads.
- The thread was blocked by a garbage collection activity.
- Other activities from custom views. This report is most effective when you identify lower-level activity within a monitored operation, then create a custom view for that activity. For example, you might have a business method that uses socket writes, so you create a custom view to monitor socket writes. If any of the outliers in the business method are caused by socket writes, the time spent in socket write is provided. You can then create a composite view which includes the socket write custom view as the secondary view. The composite view shows how the socket writes behave in combination with other events.
The Summary window
- Total events processed.
- Maximum time taken.
- Minimum time taken.
- Mean value for time taken.
- Median value for time taken.
- The standard deviation.
The Threads window
This window lists the threads that are displayed in the Plot window. Use the check boxes to control which threads are visible in the plot graph.The Histogram window
This window provides an alternative display of data. It shows a histogram representation of the data displayed in the outlier plot window. For example, in the predefined class loading view, the histogram representation shows how many class loading events took 0 - 1 ms to complete, how many events took 1 - 2 ms to complete, and so on.
The Analysis and Recommendations window
This window displays the results of analyzing the collected data. The results are in the form of a determinism score. If the number of data samples is too low, the Health Center warns you that the determinism score might not be accurate. In particular, for Java™ method-based views, where the view descriptor might match multiple methods, a warning is displayed reporting that multiple methods have been matched.
- Select all the data points in the plot window.
- Calculate the median data point value - for example, the median time taken for a class loading event.
- Find how many events fall within the following ranges:
- Median plus or minus 20% of the median value
- Median plus or minus 40% of the median value
- Median plus or minus 60% of the median value
- Median plus or minus 80% of the median value
- Median plus or minus 100% of the median value
- Calculate the average number of events for the ranges.
- The average number is the determinism score, expressed as a percentage.
Score | Meaning |
---|---|
70 or less | A very poor result. There is a wide distribution of results for the event, indicating uneven performance. |
70 - 80 | A poor result. |
80 - 90 | A good result. |
90 or more | A very good result. The results are distributed closely around the median value, indicating consistent performance. |