This white paper provides tuning recommendations to improve Oracle 10g Release 2 performance of Linux® on POWER™ to take advantage of the IBM POWER5™ and POWER5+™ processors including Red Hat’s RHEL5 new support for the POWER5+ 64 KB hardware page feature. Illustrated is how essential it is to configuring the SGA to use 16 MB huge pages when using a system with large SGAs. The paper recommends using the NOOP scheduler and demonstrates how to implement adapter tunings to reduce system interrupts. Instructions are also provided on how to bind Oracle processes to CPUs and how to set process priorities to provide additional gains.
Presented is how to link an Oracle executable with libhugetlbfs to gain performance under an OLTP workload. A very noticeable performance gain of 6% using huge page backed text segment for a Linux kernel using 4 KB pages was observed. This is a significant gain when you consider that libhugetlbfs does not require access or changes to the application source code. However, it is not recommend to use huge page data segment for OLTP–like workload due to excessive local and remote memory accesses.
Use of the latest Oracle 10g Release 2 patch set is recommended. This is certified on RHEL5 and includes the most recent Oracle performance features.
In addition, the paper provides a proof point between a 4–core and 8-core system that Oracle 10g Release 2 is capable of scaling vertically by at least 80%.