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IP OVER INFINIBAND
The ib_ipoib driver is an implementation of the IP over InfiniBand
protocol as specified by the latest Internet-Drafts issued by the
IETF ipoib working group. It is a "native" implementation in the
sense of setting the interface type to ARPHRD_INFINIBAND and the
hardware address length to 20 (earlier proprietary implementations
masqueraded to the kernel as ethernet interfaces).
Partitions and P_Keys
When the IPoIB driver is loaded, it creates one interface for each
port using the P_Key at index 0. To create an interface with a
different P_Key, write the desired P_Key into the main interface's
/sys/class/net/<intf name>/create_child file. For example:
echo 0x8001 > /sys/class/net/ib0/create_child
This will create an interface named ib0.8001 with P_Key 0x8001. To
remove a subinterface, use the "delete_child" file:
echo 0x8001 > /sys/class/net/ib0/delete_child
The P_Key for any interface is given by the "pkey" file, and the
main interface for a subinterface is in "parent."
By compiling the IPoIB driver with CONFIG_INFINIBAND_IPOIB_DEBUG set
to 'y', tracing messages are compiled into the driver. They are
turned on by setting the module parameters debug_level and
mcast_debug_level to 1. These parameters can be controlled at
runtime through files in /sys/module/ib_ipoib/.
CONFIG_INFINIBAND_IPOIB_DEBUG also enables the "ipoib_debugfs"
virtual filesystem. By mounting this filesystem, for example with
mkdir -p /ipoib_debugfs
mount -t ipoib_debugfs none /ipoib_debufs
it is possible to get statistics about multicast groups from the
files /ipoib_debugfs/ib0_mcg and so on.
The performance impact of this option is negligible, so it
is safe to enable this option with debug_level set to 0 for normal
CONFIG_INFINIBAND_IPOIB_DEBUG_DATA enables even more debug output in
the data path when data_debug_level is set to 1. However, even with
the output disabled, enabling this configuration option will affect
performance, because it adds tests to the fast path.
IETF IP over InfiniBand (ipoib) Working Group