Book description
This IBM® Redbooks® publication focuses on gathering the correct technical information, and laying out simple guidance for optimizing code performance on IBM POWER8® processor-based systems that run the IBM AIX®, IBM i, or Linux operating systems. There is straightforward performance optimization that can be performed with a minimum of effort and without extensive previous experience or in-depth knowledge.
The POWER8 processor contains many new and important performance features, such as support for eight hardware threads in each core and support for transactional memory. The POWER8 processor is a strict superset of the IBM POWER7+™ processor, and so all of the performance features of the POWER7+ processor, such as multiple page sizes, also appear in the POWER8 processor. Much of the technical information and guidance for optimizing performance on POWER8 processors that is presented in this guide also applies to POWER7+ and earlier processors, except where the guide explicitly indicates that a feature is new in the POWER8 processor.
This guide strives to focus on optimizations that tend to be positive across a broad set of IBM POWER® processor chips and systems. Specific guidance is given for the POWER8 processor; however, the general guidance is applicable to the IBM POWER7+, IBM POWER7®, IBM POWER6®, IBM POWER5, and even to earlier processors.
This guide is directed at personnel who are responsible for performing migration and implementation activities on POWER8 processor-based systems. This includes system administrators, system architects, network administrators, information architects, and database administrators (DBAs).
Table of contents
- Front cover
- Notices
- IBM Redbooks promotions
- Preface
- Summary of changes
- Chapter 1. Optimization and tuning on IBM POWER8 processor-based systems
-
Chapter 2. The IBM POWER8 processor
- 2.1 Introduction to the POWER8 processor
-
2.2 Using POWER8 features
- 2.2.1 Multi-core and multi-thread
- 2.2.2 Multipage size support (page sizes (4 KB, 64 KB, 16 MB, and 16 GB))
- 2.2.3 Efficient use of cache and memory
- 2.2.4 Transactional memory
- 2.2.5 Vector Scalar eXtension
- 2.2.6 Decimal floating point
- 2.2.7 In-core cryptography and integrity enhancements
- 2.2.8 On-chip accelerators
- 2.2.9 Storage synchronization (sync, lwsync, lwarx, stwcx., and eieio)
- 2.2.10 Fixed-point load and store quadword instructions
- 2.2.11 Instruction fusion
- 2.2.12 Event-based branches (or user-level fast interrupts)
- 2.2.13 Power management and system performance
- 2.2.14 Coherent Accelerator Processor Interface
- 2.3 I/O adapter affinity
- 2.4 Related publications
- Chapter 3. The IBM POWER Hypervisor
-
Chapter 4. IBM AIX
- 4.1 Introduction
- 4.2 Using Power Architecture features with AIX
-
4.3 AIX operating system-specific optimizations
- 4.3.1 Malloc
- 4.3.2 Pthread tunables
- 4.3.3 pollset
- 4.3.4 File system performance benefits
- 4.3.5 Direct I/O
- 4.3.6 Concurrent I/O
- 4.3.7 Asynchronous I/O
- 4.3.8 I/O completion ports
- 4.3.9 shmat versus mmap
- 4.3.10 Large segment tunable aliasing (LSA)
- 4.3.11 64-bit versus 32-bit ABIs
- 4.3.12 Sleep and wake-up primitives (thread_wait and thread_post)
- 4.3.13 Shared versus private loads
- 4.3.14 Workload partition shared licensed program installations
- 4.4 AIX preferred practices
- 4.5 Related publications
- Chapter 5. IBM i
- Chapter 6. Linux
-
Chapter 7. Compilers and optimization tools for C, C++, and Fortran
- 7.1 Compiler versions and optimization levels
- 7.2 Advanced compiler optimization techniques
- 7.3 Capitalizing on POWER8 features with the XL and GCC compilers
- 7.4 IBM Feedback Directed Program Restructuring
- 7.5 Using the Advance Toolchain with IBM XLC and XLF
- 7.6 Using GPU accelerators with C/C++
- 7.7 Related publications
- Chapter 8. Java
-
Chapter 9. IBM DB2
- 9.1 DB2 and the POWER processor
- 9.2 Taking advantage of the POWER processor
- 9.3 Capitalizing on the compilers and optimization tools for POWER
- 9.4 Capitalizing on POWER virtualization
- 9.5 Capitalizing on the AIX system libraries
- 9.6 Capitalizing on performance tools
- 9.7 Conclusion
- 9.8 Related publications
- Chapter 10. IBM WebSphere Application Server
- Appendix A. Analyzing malloc usage under IBM AIX
- Appendix B. Performance tools and empirical performance analysis
- Back cover
Product information
- Title: Performance Optimization and Tuning Techniques for IBM Power Systems Processors Including IBM POWER8
- Author(s):
- Release date: August 2015
- Publisher(s): IBM Redbooks
- ISBN: 9780738440927
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