HPjmeter 4.3 User's Guide

Profiling from HPjmeter with Zero Preparation........................................................................74
Configuring Remote Operations window...............................................................................75
Profiling with -agentlib:hprof................................................................................................76
Naming Profile Data Files...................................................................................................78
Profiling with jmap.............................................................................................................79
–Xeprof and –agentlib:hprof Profiling Options and Their Corresponding Metrics.............................79
Approaches to Analyzing Performance Data..............................................................................81
Looking at the Data from the Bottom Up................................................................................81
Looking at the Data from the Top Down................................................................................82
Looking for Inefficiencies in Memory Usage...........................................................................82
Considerations in Interpreting the Data......................................................................................82
Inclusive Versus Exclusive Time.............................................................................................82
Time Units.........................................................................................................................82
CPU Versus Clock Time..................................................................................................83
Locating Summary Information for Saved Data Sets.....................................................................83
Adjusting Scope.....................................................................................................................83
Comparing Profiling Data Files ................................................................................................85
Scaling Comparison Data........................................................................................................86
Reading Profiling Histograms...................................................................................................87
Key to Thread States Reported by ........................................................................................87
Interpreting the Histogram Presentation.................................................................................89
Using Call Graph Trees...........................................................................................................89
Interpreting Call Graph Data...............................................................................................90
Example of Node Color Display......................................................................................90
Options for Manipulating the Call Tree Display......................................................................91
Tree Pruning.................................................................................................................91
Auto-Expanding the Call Tree.........................................................................................91
Using Sub-Trees............................................................................................................91
Searching the Trees.......................................................................................................92
Using Heuristics to Locate Possible Hot Spots..............................................................................92
6 Analyzing Garbage Collection Data ..........................................................94
Obtaining Garbage Collection Data.........................................................................................94
Data Collection with -Xverbosegc.........................................................................................94
Collecting Allocation Site Statistics for Viewing in HPjmeter.................................................98
Collecting Glance Data for Viewing in HPjmeter...............................................................98
Collecting GC Data with Zero Preparation............................................................................99
Data Collection with -Xloggc.............................................................................................100
Naming GC Data Files.....................................................................................................101
-Xverbosegc and -Xloggc Options and Their Corresponding Metrics............................................101
Locating Summary Information for Saved Data Sets...................................................................102
Comparing Garbage Collection Data Files ..............................................................................102
Basic Garbage Collection Concepts........................................................................................103
Key to Garbage Collection Types Recognized by HPjmeter....................................................103
Understanding the Summary Presentation of GC Data..........................................................105
Understanding the System Details Captured with GC Data....................................................107
7 Using the Console .................................................................................110
Starting the Console..............................................................................................................110
Starting the Console On HP-UX..........................................................................................110
Starting the Console On Linux...........................................................................................110
Starting the Console On Microsoft Windows.......................................................................110
Using the Main Window Functions.........................................................................................110
Data Representation.........................................................................................................111
Icons and Their Meaning..................................................................................................112
Node Agent...............................................................................................................112
14 Contents