User guide

3–InfiniBand
®
Cluster Setup and Administration
Performance Settings and Management Tips
IB0054606-02 A 3-25
Performance Tuning
Tuning compute or storage (client or server) nodes with IB HCAs for MPI and
verbs performance can be accomplished in several ways:
 Run the ipath_perf_tuning script in automatic mode (See
“Performance Tuning using ipath_perf_tuning Tool” on page 3-34)
(easiest method)
 Run the ipath_perf_tuning script in interactive mode (See
“Performance Tuning using ipath_perf_tuning Tool” on page 3-34 or
see man ipath_perf_tuning). This interactive mode allows more
control, and should be used for tuning storage (client or server) nodes.
 Make changes to ib_qib driver parameter files, the BIOS or system
services using the information provided in the following sections
Systems in General (With Either Intel or AMD CPUs)
For best performance on dual-port HCAs on which only one port is active, the
module parameter line in the modprobe.conf file should include the following:
options ib_qib singleport=1
Services
Turn off the specified daemons using one of the following commands according to
which OS is being used:
 For RHEL or similar systems use:
/sbin/chkconfig --level 12345 cpuspeed off
 For SLES systems use:
/sbin/chkconfig --level 12345 powersaved off
NOTE
The modprobe configuration file (modprobe.conf) will be used in this
section for the ib_qib module configuration file, which has various paths and
names in the different Linux distributions as shown in the following list:
 For RHEL 5.x use file: /etc/modprobe.conf
 For SLES 10 or 11 use file: /etc/modprobe.conf.local
 For RHEL 6.x use file:/etc/modprobe.d/ib_qib.conf