User guide

3–InfiniBand
®
Cluster Setup and Administration
Performance Settings and Management Tips
IB0054606-02 A 3-37
Applying the Results
Automatic mode versus interactive mode also has an effect when the tool is
committing the changes to the system. Along with the necessary driver
parameters, the script also writes a comment line in the appropriate file which
serves as a marker. This marker contains the version of the script which is making
the changes. If the version recorded matches the version of the script currently
being run, the changes are only committed if the tool is in interactive mode. The
assumption is that the script is being re-run by the user to make adjustments.
Affected Files
The following lists the distribution and the file that is modified by the
ipath_perf_tuning tool:
 RHEL 6.0 and later – /etc/modprobe.d/ib_qib.conf
 RHEL prior to 6.0 – /etc/modprobe.conf
 SLES – /etc/modprobe.conf.local
Homogeneous Nodes
To minimize management problems, the compute nodes of the cluster should
have very similar hardware configurations and identical software installations. A
mismatch between the software versions can also cause problems. Old and new
libraries must not be run within the same job. It may also be useful to distinguish
between the IB-specific drivers and those that are associated with kernel.org,
OpenFabrics, or are distribution-built. The most useful tools are:

ident (see “ident” on page G-24)

ipathbug-helper (see “ipath_checkout” on page G-25)

ipath_checkout (see “ipath_checkout” on page G-25)

ipath_control (see “ipath_control” on page G-27)

mpirun (see “mpirun” on page G-31)
services Test is performed in both modes but the user is noti-
fied of running services only if the tool is in interac-
tive mode. In that case, the user is queried whether
to turn the services off.
Table 3-5. Test Execution Modes
Test Mode