DTrace

The first guide to DTrace: the breakthrough debugging tool for Mac OS X, Unix, Solaris, and OpenSolaris operating systems and applications

Complete coverage: architecture, implementation, components, usage, and much more Covers integrating DTrace into open source code, and integrating probes into application software Includes full chapter of advanced tips and techniques For users of DTrace on all platforms Foreword by Bryan Cantril, creator of DTrace

DTrace represents a revolution in debugging. Using it, administrators, developers, and service personnel can dynamically instrument operating systems and applications to quickly ask and answer virtually any question about how their operating systems or user programs are behaving. Now available for Solaris 10 and OpenSolaris, Mac OS X, and FreeBSD, thousands of professionals are discovering DTrace - but, until now, there's been no comprehensive, authoritative guide to using it. This book fills that gap. Written by four key contributors to the DTrace community, it's the first single source reference to this powerful new technology. The authors cover everything technical professionals need to know to succeed with DTrace, regardless of the operating system or application they want to instrument. The book also includes a full chapter of advanced tips and techniques.

Autorentext

Brendan Gregg is a performance specialist at Joyent and is known worldwide in the field of DTrace. Brendan created and developed the DTraceToolkit and is the coauthor of SolarisTM Performance and Tools (Prentice Hall, 2006) as well as numerous articles about DTrace. Many of Brendan's DTrace scripts are shipped by default in Mac OS X.

Jim Mauro is a senior software engineer for Oracle Corporation, working in the Systems group with a primary focus on systems performance. Jim has 30 years of experience in the computer industry and coauthored SolarisTM Performance and Tools and the first and second editions of SolarisTM Internals (Sun Microsystems Press, 2000, and Prentice Hall, 2006).

Klappentext

The Oracle Solaris DTrace feature revolutionizes the way you debug operating systems and applications. Using DTrace, you can dynamically instrument software and quickly answer virtually any question about its behavior. Now, for the first time, there's a comprehensive, authoritative guide to making the most of DTrace in any supported UNIX environment--from Oracle Solaris to OpenSolaris, Mac OS X, and FreeBSD.

Written by key contributors to the DTrace community, DTrace teaches by example, presenting scores of commands and easy-to-adapt, downloadable D scripts. These concise examples generate answers to real and useful questions, and serve as a starting point for building more complex scripts. Using them, you can start making practical use of DTrace immediately, whether you're an administrator, developer, analyst, architect, or support professional.

The authors fully explain the goals, techniques, and output associated with each script or command. Drawing on their extensive experience, they provide strategy suggestions, checklists, and functional diagrams, as well as a chapter of advanced tips and tricks. You'll learn how to

• Write effective scripts using DTrace's D language

• Use DTrace to thoroughly understand system performance

• Expose functional areas of the operating system, including I/O, filesystems, and protocols

• Use DTrace in the application and database development process

• Identify and fix security problems with DTrace

• Analyze the operating system kernel

• Integrate DTrace into source code

• Extend DTrace with other tools

This book will help you make the most of DTrace to solve problems more quickly and efficiently, and build systems that work faster and more reliably.

Inhalt

Foreword xxi

Preface xxv

Acknowledgments xxxi

About the Authors xxxv

Part I: Introduction

Chapter 1: Introduction to DTrace 1

What Is DTrace? 1

Why Do You Need It? 1

Capabilities 2

Dynamic and Static Probes 4

DTrace Features 4

A First Look 6

Overview 8

Architecture 16

Summary 17

Chapter 2: D Language 19

D Language Components 20

Probes 23

Variables 26

Aggregations 33

Actions 37

Options 43

Example Programs 44

Summary 49

Part II: Using DTrace

Chapter 3: System View 51

Start at the Beginning 52

Observing CPUs 56

Observing Memory 95

Observing Disk and Network I/O 125

Summary 148

Chapter 4: Disk I/O 151

Capabilities 152

Disk I/O Strategy 154

Checklist 155

Providers 156

Scripts 172

Case Studies 269

Summary 290

Chapter 5: File Systems 291

Capabilities 292

Strategy 295

Checklist 296

Providers 297

Scripts 313

Case Study 387

Summary 397

Chapter 6: Network Lower-Level Protocols 399

Capabilities 400

Strategy 402

Checklist 403

Providers 404

Scripts 445

Common Mistakes 548

Summary 555

Chapter 7: Application-Level Protocols 557

Capabilities 558

Strategy 558

Checklist 559

Providers 560

Scripts 574

Summary 668

Chapter 8: Languages 669

Capabilities 671

Strategy 672

Checklist 674

Providers 675

C 679

C++ 689

Java 691

JavaScript 705

Perl 719

PHP 731

Python 740

Ruby 751

Shell 764

Tcl 774

Summary 782

Chapter 9: Applications 783

Capabilities 784

Strategy 784

Checklist 786

Providers 787

Scripts 804

Case Studies 817

Summary 832

Chapter 10: Databases 833

Capabilities 834

Strategy 835

Providers 836

MySQL 837

PostgreSQL 851

Oracle 858

Summary 865

Part III: Additional User Topics

Chapter 11: Security 867

Privileges, Detection, and Debugging 867

Scripts 875

Summary 892

Chapter 12: Kernel 893

Capabilities 894

Strategy 896

Checklist 897

Providers 897

Scripts 932

Summary 945

Chapter 13: Tools 947

The DTraceToolkit 948

Chime 962

DTrace GUI Plug-in for NetBeans and Sun Studio 966

DLight, Oracle Solaris Studio 12.2 966

Mac OS X Instruments 971

Analytics 973

Summary 985

Chapter 14: Tips and Tricks 987

Tip 1: Known Workloads 987

Tip 2: Write Target Software 989

Tip 3: Use grep to Search for Probes 991

Tip 4: Frequency Count 991

Tip 5: Time Stamp Column, Postsort 992

Tip 6: Use Perl to Postprocess 993

Tip 7: Learn Syscalls 994

Tip 8: timestamp vs. vtimestamp 995

Tip 9: profile:::profile-997 and Profiling 996

Tip 10: Variable Scope and Use 997

Tip 11: strlen() and strcmp() 999

Tip 12: Check Assumptions 1000

Tip 13: Keep It Simple 1001

Tip 14: Consider Performance Impact 1001

Tip 15: drops and dynvardrops 1003

Tip 16: Tail-Call Optimization 1003

Further Reading 1003

Appendix A: DTrace Tunable Variables 1005

Appendix B: D Language Reference 1011

Appendix C: Provider Arguments Reference 1025

Providers 1025

Arguments 1038

Appendix D: DTrace on FreeBSD 1045

Enabling DTrace on FreeBSD 7.1 and 8.0 1045

DTrace for FreeBSD: John Birrell 1047

Appendix E: USDT Example 1051

USDT Bourne Shell Provider 1052

Case Study: Implementing a Bourne Shell Provider 1057

Appendix F: DTrace Error Messages 1063

Privileges 1063

Drops 1064

Aggregation Drops 1065

Dynamic Variable Drops 1066

Invalid Address 1066

Maximum Program Size 1067

Not Enough Space 1068

Appendix G: DTrace Cheat Sheet 1069

Synopsis 1069

Finding Probes 1069

Finding Probe Arguments 1070

Probes 1070

Vars 1070

Actions 1071

Switches 1071

Pragmas 1071

One-Liners 1072

Bibliography 1073

Suggested Reading 1073

Vendor Manuals 1075

Index 1089