= Getting Started with Performance Data Analyzer (PDA)
PDA is a tool for analysis and correlation of performance data, as well as for report generation. This short introduction explains how to interactively load performance data into PDA and work with it.
== Generating some Data
Before we can load data, we need some. PDA comes with a small demo which generates a CSV-based logfile, as well as a Java Garbage Collection logfile. Please run
This will run for five minutes and generate a CSV file named ''demo.csv'' and a garbage collection logfile ''javagc.log''.
== Start the Performance Data Analyzer
To run the PDA GUI, start:
== Loading Data into PDA
Click on ''Configure Project'' to configure the current (unnamed) project.
Now we want to add some files to this project. Click on ''Select'' and select the Garbage Collection logfile ''javagc.log'' that was just generated. A window ''Select Parser'' appears. PDA automatically tries to determine which parser it thinks can handle this file. If not already preselected, please chose ''gc (de.nmichael.pda.parser.Gc)'' as the parser. In the table below, each parser provides some information on the data it can handle. Click ''OK'' to open and parse the file.
== Selecting Data Series to Plot
All data provided by parsers is organized in ''categories'', which contain one or multiple ''series''. It is very much up to the parser, how data is organized. For example, the ''iostat'' parser would provide each device as a ''category'', and expose values such as ''r/s'', ''w/s'' etc. as series.
To add a series, click the ''Add Series'' button of that parser. For plotting our GC output, select category ''newgen'' (which contains all events for garbage collection in the New Generation). To select all series of this category at once, scroll down in the ''series'' selection to the bottom and select ''--- all ---''. PDA will now add all these series to the project, and automatically chose colors, styles and value ranges to plot them.
To change some attributes, now click on the ''Configure'' button of series ''gc:newgen:yheap'' (which is the current Young Heap occupancy). For test purposes, change the maximum value of the Y axis (''Range Y to'') to ''2.0E11'' (that's ''200000000000.0''), and change the parameter ''Value Axis'' to ''logarithmic''. Click ''OK''.
Now in the ''Configure Project'' dialog, enter a ''Project Name'' (for example, ''GC Demo''), and click ''OK'' to plot the data.
== Plotted Data
All data plotted by PDA is value-time-based. All samples are aligned along a common time axis (X axis). Each series of data may have an individual scale on the value axis (Y axis). On the top of the screen, each series' name can be found in the color used to plot that series. Underneath the name, you can see the value range. For example, series ''gc:newgen:yhead'' that we have edited before is plotted in red, using a value range from 0.0 to 2.0E11 on the Y axis.
Note also that different styles are used for the data. Most series are plotted using lines. Only series ''gc:newgen:gctime'' (the pause times for garbage collections in the young generation) are plotted using dots.
On the right side of the screen, click the button with the green label ''gc:newgen:gctime''. A window named ''Series Statistics"" will pop up and display some statistics about this series, as the number of found samples within the selected time frame, Min/Max/Avg/Variance/Standard Deviation for this series, as well as the Min/Max/Avg distance between samples. In terms of garbage collection times, the ''Avg Distance'' is our average garbage collection interval, and the ''Avg Value'' is the average time (in this case in milliseconds) for a garbage collection. Click ''OK'' to close the window again.
With the mouse, you can zoom into data more closely, by selecting a certain part of the graph. Note that zooming will only zoom in on the X axis, not the Y axis. For example, zoom into the letter ''V'' of the plotted data. Now click the statistics button for series ''gc:newgen:gctime'' again and note that now the statistics only reflect the samples from the selected interval. After closing the statistics window, click the ''Reset Zoom'' button to reset the zoom.
By clicking ''Add Label'', you can add a label to the graph and drag it to a position you like.
== Adding more Data
Click on ''Configure Project'' again to add more data. Click ''Select'' and select the ''demo.csv'' file that was generated earlier. Select parser ''csv (de.nmichael.pda.parser.Csv)'' and click ''OK'' to open and parse the data. Then click on ''Add Series'' for the ''demo.csv'' data, select category ''Samples'' and series ''value'' and click ''OK''. Now click ''Configure'' on the just added series and change the ''Line Width'' to ''10''. Click ''OK'', and ''OK'' in the ''Configure Project'' dialog to plot the data.
The purple line from the CSV parser shows the curve that the demo was trying to plot. In shape, it should match the GC output. To better align it with the rest of the data, change the selection on the right side of the screen from ''Series Statistics...'' to ''Configure Series...'', and click on the ''csv:Samples:value'' series button below. This is a shortcut to change the properties of a series without going though ''Configure Project''. Change ''Range Y to'' to ''1.5E8'' and click ''OK''.
== Saving a Project
To save the project, select ''Save as...'' from the ''Project'' menu and save the project. It can then later be opened again.
To save the current displayed data as a PNG image, click the ''Save Image'' button or select ''Save As Image...'' from the ''Project'' menu.