Dtrace

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.

An in-depth look into Mac OS X and iOS kernels Powering Macs, iPhones, iPads and more, OS X and iOS are becoming ubiquitous. When it comes to documentation, however, much of them are shrouded in mystery. Cocoa and Carbon, the application frameworks, are neatly described, but system programmers find the rest lacking. This indispensable guide illuminates the darkest corners of those systems, starting with an architectural overview, then drilling all the way to the core. Provides you with a top down view of OS X and iOS Walks you through the phases of system startup—both Mac (EFi) and mobile (iBoot) Explains how processes, threads, virtual memory, and filesystems are maintained Covers the security architecture Reviews the internal Apis used by the system—BSD and Mach Dissects the kernel, XNU, into its sub components: Mach, the BSD Layer, and I/o kit, and explains each in detail Explains the inner workings of device drivers From architecture to implementation, this book is essential reading if you want to get serious about the internal workings of Mac OS X and iOS.

Use BPF Tools to Optimize Performance, Fix Problems, and See Inside Running Systems BPF-based performance tools give you unprecedented visibility into systems and applications, so you can optimize performance, troubleshoot code, strengthen security, and reduce costs. BPF Performance Tools: Linux System and Application Observability is the definitive guide to using these tools for observability. Pioneering BPF expert Brendan Gregg presents more than 150 ready-to-run analysis and debugging tools, expert guidance on applying them, and step-by-step tutorials on developing your own. You’ll learn how to analyze CPUs, memory, disks, file systems, networking, languages, applications, containers, hypervisors, security, and the kernel. Gregg guides you from basic to advanced tools, helping you generate deeper, more useful technical insights for improving virtually any Linux system or application. • Learn essential tracing concepts and both core BPF front-ends: BCC and bpftrace • Master 150+ powerful BPF tools, including dozens created just for this book, and available for download • Discover practical strategies, tips, and tricks for more effective analysis • Analyze compiled, JIT-compiled, and interpreted code in multiple languages: C, Java, bash shell, and more • Generate metrics, stack traces, and custom latency histograms • Use complementary tools when they offer quick, easy wins • Explore advanced tools built on BPF: PCP and Grafana for remote monitoring, eBPF Exporter, and kubectl-trace for tracing Kubernetes • Foreword by Alexei Starovoitov, creator of the new BPF BPF Performance Tools will be an indispensable resource for all administrators, developers, support staff, and other IT professionals working with any recent Linux distribution in any enterprise or cloud environment.

Learn to find software bugs faster and discover how other developers have solved similar problems. For intermediate to advanced iOS/macOS developers already familiar with either Swift or Objective-C who want to take their debugging skills to the next level, this book includes topics such as: LLDB and its subcommands and options; low-level components used to extract information from a program; LLDB's Python module; and DTrace and how to write D scripts.

The most complete, authoritative technical guide to the FreeBSD kernel’s internal structure has now been extensively updated to cover all major improvements between Versions 5 and 11. Approximately one-third of this edition’s content is completely new, and another one-third has been extensively rewritten. Three long-time FreeBSD project leaders begin with a concise overview of the FreeBSD kernel’s current design and implementation. Next, they cover the FreeBSD kernel from the system-call level down–from the interface to the kernel to the hardware. Explaining key design decisions, they detail the concepts, data structures, and algorithms used in implementing each significant system facility, including process management, security, virtual memory, the I/O system, filesystems, socket IPC, and networking. This Second Edition • Explains highly scalable and lightweight virtualization using FreeBSD jails, and virtual-machine acceleration with Xen and Virtio device paravirtualization • Describes new security features such as Capsicum sandboxing and GELI cryptographic disk protection • Fully covers NFSv4 and Open Solaris ZFS support • Introduces FreeBSD’s enhanced volume management and new journaled soft updates • Explains DTrace’s fine-grained process debugging/profiling • Reflects major improvements to networking, wireless, and USB support Readers can use this guide as both a working reference and an in-depth study of a leading contemporary, portable, open source operating system. Technical and sales support professionals will discover both FreeBSD’s capabilities and its limitations. Applications developers will learn how to effectively and efficiently interface with it; system administrators will learn how to maintain, tune, and configure it; and systems programmers will learn how to extend, enhance, and interface with it. Marshall Kirk McKusick writes, consults, and teaches classes on UNIX- and BSD-related subjects. While at the University of California, Berkeley, he implemented the 4.2BSD fast filesystem. He was research computer scientist at the Berkeley Computer Systems Research Group (CSRG), overseeing development and release of 4.3BSD and 4.4BSD. He is a FreeBSD Foundation board member and a long-time FreeBSD committer. Twice president of the Usenix Association, he is also a member of ACM, IEEE, and AAAS. George V. Neville-Neil hacks, writes, teaches, and consults on security, networking, and operating systems. A FreeBSD Foundation board member, he served on the FreeBSD Core Team for four years. Since 2004, he has written the “Kode Vicious” column for Queue and Communications of the ACM. He is vice chair of ACM’s Practitioner Board and a member of Usenix Association, ACM, IEEE, and AAAS. Robert N.M. Watson is a University Lecturer in systems, security, and architecture in the Security Research Group at the University of Cambridge Computer Laboratory. He supervises advanced research in computer architecture, compilers, program analysis, operating systems, networking, and security. A FreeBSD Foundation board member, he served on the Core Team for ten years and has been a committer for fifteen years. He is a member of Usenix Association and ACM.

The Complete Guide to Optimizing Systems Performance Written by the winner of the 2013 LISA Award for Outstanding Achievement in System Administration Large-scale enterprise, cloud, and virtualized computing systems have introduced serious performance challenges. Now, internationally renowned performance expert Brendan Gregg has brought together proven methodologies, tools, and metrics for analyzing and tuning even the most complex environments. Systems Performance: Enterprise and the Cloud focuses on Linux® and Unix® performance, while illuminating performance issues that are relevant to all operating systems. You’ll gain deep insight into how systems work and perform, and learn methodologies for analyzing and improving system and application performance. Gregg presents examples from bare-metal systems and virtualized cloud tenants running Linux-based Ubuntu®, Fedora®, CentOS, and the illumos-based Joyent® SmartOSTM and OmniTI OmniOS®. He systematically covers modern systems performance, including the “traditional” analysis of CPUs, memory, disks, and networks, and new areas including cloud computing and dynamic tracing. This book also helps you identify and fix the “unknown unknowns” of complex performance: bottlenecks that emerge from elements and interactions you were not aware of. The text concludes with a detailed case study, showing how a real cloud customer issue was analyzed from start to finish. Coverage includes • Modern performance analysis and tuning: terminology, concepts, models, methods, and techniques • Dynamic tracing techniques and tools, including examples of DTrace, SystemTap, and perf • Kernel internals: uncovering what the OS is doing • Using system observability tools, interfaces, and frameworks • Understanding and monitoring application performance • Optimizing CPUs: processors, cores, hardware threads, caches, interconnects, and kernel scheduling • Memory optimization: virtual memory, paging, swapping, memory architectures, busses, address spaces, and allocators • File system I/O, including caching • Storage devices/controllers, disk I/O workloads, RAID, and kernel I/O • Network-related performance issues: protocols, sockets, interfaces, and physical connections • Performance implications of OS and hardware-based virtualization, and new issues encountered with cloud computing • Benchmarking: getting accurate results and avoiding common mistakes This guide is indispensable for anyone who operates enterprise or cloud environments: system, network, database, and web admins; developers; and other professionals. For students and others new to optimization, it also provides exercises reflecting Gregg’s extensive instructional experience.

As more and more vulnerabilities are found in the Mac OS X (Leopard) operating system, security researchers are realizing the importance of developing proof-of-concept exploits for those vulnerabilities. This unique tome is the first book to uncover the flaws in the Mac OS X operating system—and how to deal with them. Written by two white hat hackers, this book is aimed at making vital information known so that you can find ways to secure your Mac OS X systems, and examines the sorts of attacks that are prevented by Leopard’s security defenses, what attacks aren’t, and how to best handle those weaknesses.