Q-Logic Computer Drive IB0056101-00 G Benutzerhandbuch

5 – Software Installation
Other Configuration: Changing the MTU Size

5-26

IB0056101-00  G

S

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

.

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 

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. 

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

information on creating mount points.

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