IBM Power7 Optimization And Tuning Manual page 210

This publication directly addresses three main areas in which POWER7 differs from
POWER5 and POWER6: SMT4 mode, the virtual processor folding algorithm, and
overall throughput.
Kernel tuning parameters are presented in detail, particularly regarding memory and I/O,
and closely resemble preferred practices for Oracle.
The section Processor Considerations addresses the implications of SMT4 mode for
allocation of Sybase ASE engines, the implications of the POWER7 virtual processor
allocation algorithms on sizing ASE in a shared pool environment, and general preferred
practices for aligning Sybase ASE resources with entitlement and virtual processor count.
The same section of this paper addresses the non-traditional technique of allocating more
Sybase ASE engines than there are AIX virtual processors or cores. In particular, you
should not exceed a ratio of two engines per virtual processor, even with SMT4
mode enabled.
Suggestions to reduce SMT mode to 2 or even ST mode for Sybase ASE and suggestions
to turn off virtual processor folding are noted. Most of clients get the best performance
from Sybase ASE on AIX/POWER7 with SMT4 mode and virtual processor
folding enabled.
Appendix A of this paper presents an iterative tuning exercise with Sybase ASE 15.5, AIX
V7.1, and POWER7. Results are presented for the TPC-C benchmark and other
workloads, which indicate that the SMT4 mode provides superior or equal performance
when compared to SMT2 and ST modes.
Migrating Sybase ASE to IBM Power Systems, available at:
http://www.ibm.com/support/techdocs/atsmastr.nsf/WebIndex/WP102105
The subtitle of this paper explains its purpose: It presents the case for POWER7 as the
optimal platform for Sybase ASE, presents guidelines and preferred practices for
migrations, and includes a field guide to migrations and proofs of concept.
Many sections of this paper are useful for systems and database managers in planning
and carrying out migrations of Sybase ASE to POWER7.
Part I includes a description about Cross Platform Dump and Load (XPDL), the most
widely used ASE migration technique, including preparation and post-migration cleanup
steps. Other migration techniques are also described. The implications of upgrading ASE
from Version 12.5 to Version 15.x, as part of a platform migration, are also described, and
some preferred practices are offered. Specific scenarios and case studies are cited,
including scale-ups and consolidations. Shared processor and virtualization concepts are
reviewed in the context of Sybase ASE.
In Part II, the "Field guide to migrations and proofs of concept", the first section on
requirements gathering, presents a detailed list of configuration information and
performance data to be collected in preparation for a migration to POWER7.
In Part III, commonly encountered problems in migrating Sybase ASE to POWER7 are
identified and described in some detail.
A list of configuration and performance data to collect when you troubleshoot a
performance issue is provided.
Several performance scenarios are described and compared: The case of spinlock
healthy
contention is contrasted with a CPU-bound workload. Likewise, the case of idling
engines because of overallocation is contrasted with a healthy I/O-bound workload.
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POWER7 and POWER7+ Optimization and Tuning Guide