Q-Logic IB0056101-00 G manual Other Configuration Changing the MTU Size, MPI over uDAPL

5 – Software Installation

Other Configuration: Changing the MTU Size

S

NOTE:

Use sde1 rather than sde. See the mount(8) man page for more information on creating mount points.

MPI over uDAPL

Some MPI implementations, such as Intel MPI and HP-MPI, can be run over uDAPL. uDAPL is the user mode version of the Direct Access Provider Library (DAPL). Examples of these types of MPI implementations are Intel MPI and one option on Open MPI.

If you are running this type of MPI implementation, the rdma_cm and rdma_ucm modules will need to be loaded. To load these modules, use these commands (as root):

#modprobe rdma_cm

#modprobe rdma_ucm

To ensure that the modules are loaded whenever the driver is loaded, add rdma_cm and rdma_ucm to the OPENFABRICS_MODULES assignment in /etc/sysconfig/infinipath.

Other Configuration: Changing the MTU Size

The Maximum Transfer Unit (MTU) is set to 4K and enabled in the driver by default. To change the driver default back to 2K MTU, add this line (as root) in

/etc/modprobe.conf (or in /etc/modprobe.conf.local on SLES):

options ib_ipath mtu4096=0

Restart the driver as described in “Starting and Stopping the InfiniPath Software” on page 5-26.

NOTE:

The switch must also have the default set to 4K.

Starting and Stopping the InfiniPath Software

The InfiniPath driver software runs as a system service, usually started at system startup. Normally, you will not need to restart the software, but you may want to after installing a new InfiniPath release, after changing driver options, or when you are doing manual testing.

Use the following commands to check or configure the state. These methods will not reboot the system.

5-26 IB0056101-00 G