IBM Power7 - Low-Level Investigation; Conclusion; Related Publications

144 POWER7 and POWER7+ Optimization and Tuning Guide
8.6.2 Low-level investigation
Various system level tools are essential in drilling down to find a potential root cause for the
type of the bottlenecks that are listed in 8.6, “Capitalizing on performance tooling” on
page 143. Profiling tools are especially invaluable for identifying CPU bound issues and are
available on AIX and Linux platforms for POWER7.
AIX tprof
tprof is a powerful profiling tool on AIX and Linux platforms that does program
counter-sampling in clock interrupts. It can work on any binary without recompilation and is a
great tool for codepath analysis.
For instructions about using tprof, go to the AIX V7.1 Information Center and search for tprof
command at:
http://pic.dhe.ibm.com/infocenter/aix/v7r1/index.jsp?topic=/com.ibm.aix.cmds/doc/a
ixcmds5/tprof.htm/
AIX tprof microprofiling
Beyond the high-level tprof profiling, DB2 also uses the microprofiling option of tprof during
development. Microprofiling allows DB2 to perform instruction level profiling to attributes the
CPU time spent on source program lines.
Linux OProfile
OProfile is a system profiling tool, similar in nature to tprof, that is popular on the Linux
platform. OProfile uses hardware counters to provide functional level profiling in both the
kernel and user space. Like tprof, this tool is useful during DB2 development for
codepath analysis.
For more information about this topic, see 8.8, “Related publications” on page 144.
8.7 Conclusion
DB2 is positioned to capitalize on many Power features to maximize the ROI of the full IBM
stack. During the entire DB2 development cycle, there is a targeted effort to take advantage of
Power features and ensure that the highest level of optimization is employed on this platform.
With every new Power generation, DB2 ensures that the key features are supported and
brought into play at Power launch time, by working on such features well in advance of
general availability. This type of targeted effort ensures that DB2 is at the forefront of
optimization for Power applications.
8.8 Related publications
The publications that are listed in this section are considered suitable for a more detailed
discussion of the topics that are covered in this chapter:
򐂰 Best Practices for DB2 on AIX 6.1 for Power Systems, SG24-7821
򐂰 Best practices for DB2 for Linux, UNIX, and Windows, found at:
http://www.ibm.com/developerworks/data/bestpractices/db2luw/