User guide

D–Troubleshooting
Open MPI Troubleshooting
D-12 IB0054606-02 A
Performance Warning if ib_qib Shares Interrupts with eth0
When ib_qib shares interrupts with eth0, performance may be affected the
OFED ULPs, such as IPoIB. A warning message appears in syslog, and also on
the console or tty session where /etc/init.d/openibd start is run (if
messages are set up to be displayed). Messages are in this form:
Nov 5 14:25:43 <nodename> infinipath: Shared interrupt will
affect performance: vector 169: devices eth0, ib_qib
Check /proc/interrupts: "169" is in the first column, and "devices" are shown
in the last column.
You can also contact your system vendor to see if the BIOS settings can be
changed to avoid the problem.
Open MPI Troubleshooting
Problems specific to compiling and running Open MPI programs are described in
the following sections.
Invalid Configuration Warning
Open MPI warns about a invalid configuration every time it is run with the
following warning:
WARNING: There are more than one active ports on host
'st2107', but the default subnet GID prefix was detected on
more than one of these ports. If these ports are connected to
different physical IB networks, this configuration will fail
in Open MPI. This version of Open MPI requires that every
physically separate IB subnet that is used between connected
MPI processes must have different subnet ID values.
When connecting 2 ports of an HCA to different fabrics, it is a mandatory
requirement that the SubnetPrefix for those two fabrics be different and
non-default (for example, not FE80000000000000) based on the Fabric Manager
configuration file. The config_generate tool for the Fabric Manager will help
generate such files. Refer to the QLogic Fabric Manager User Guide for more
information about the config_generate tool.