HPjmeter 4.2 User's Guide

Profiling with -Xeprof......................................................................................................................61
Profiling with Zero Preparation......................................................................................................62
Profiling with -agentlib:hprof..........................................................................................................63
Naming Profile Data Files...............................................................................................................65
–Xeprof and –agentlib:hprof Profiling Options and Their Corresponding Metrics.............................65
Approaches to Analyzing Performance Data.......................................................................................68
Looking at the Data from the Bottom Up........................................................................................68
Looking at the Data from the Top Down........................................................................................68
Looking for Inefficiencies in Memory Usage..................................................................................68
Considerations in Interpreting the Data...............................................................................................68
Inclusive Versus Exclusive Time.....................................................................................................69
Time Units.......................................................................................................................................69
CPU Versus Clock Time.............................................................................................................69
Locating Summary Information for Saved Data Sets...........................................................................69
Adjusting Scope....................................................................................................................................70
Comparing Profiling Data Files ...........................................................................................................71
Scaling Comparison Data.....................................................................................................................72
Reading Profiling Histograms..............................................................................................................73
Key to Thread States Reported by ..................................................................................................73
Interpreting the Histogram Presentation........................................................................................74
Using Call Graph Trees.........................................................................................................................75
Interpreting Call Graph Data..........................................................................................................75
Example of Node Color Display................................................................................................76
Options for Manipulating the Call Tree Display.............................................................................77
Tree Pruning...............................................................................................................................77
Auto-Expanding the Call Tree...................................................................................................77
Using Sub-Trees..........................................................................................................................77
Searching the Trees.....................................................................................................................78
Using Heuristics to Locate Possible Hot Spots.....................................................................................78
6 Analyzing Garbage Collection Data .......................................................................80
Obtaining Garbage Collection Data......................................................................................................80
Data Collection with -Xverbosegc...................................................................................................80
Collecting Allocation Site Statistics for Viewing in HPjmeter...................................................83
Collecting Glance Data for Viewing in HPjmeter......................................................................83
Collecting GC Data with Zero Preparation.....................................................................................83
Data Collection with -Xloggc...........................................................................................................84
Naming GC Data Files.....................................................................................................................85
-Xverbosegc and -Xloggc Options and Their Corresponding Metrics.................................................85
Locating Summary Information for Saved Data Sets...........................................................................86
Comparing Garbage Collection Data Files ..........................................................................................86
Basic Garbage Collection Concepts......................................................................................................87
Key to Garbage Collection Types Recognized by HPjmeter...........................................................87
Understanding the Summary Presentation of GC Data..................................................................88
Understanding the System Details Captured with GC Data..........................................................90
7 Using the Console .......................................................................................................93
Starting the Console..............................................................................................................................93
Starting the Console On HP-UX......................................................................................................93
Starting the Console On Linux........................................................................................................93
Starting the Console On Microsoft Windows..................................................................................93
Using the Main Window Functions......................................................................................................93
Data Representation........................................................................................................................94
Icons and Their Meaning.................................................................................................................95
Node Agent................................................................................................................................95
JVM Agent..................................................................................................................................95
Table of Contents 5