b1ed8dab94
Update IPoIB documentation now that multicast debugging files have moved from ipoibdebugfs to debugfs. Signed-off-by: Roland Dreier <roland@topspin.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
56 lines
2.2 KiB
Plaintext
56 lines
2.2 KiB
Plaintext
IP OVER INFINIBAND
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The ib_ipoib driver is an implementation of the IP over InfiniBand
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protocol as specified by the latest Internet-Drafts issued by the
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IETF ipoib working group. It is a "native" implementation in the
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sense of setting the interface type to ARPHRD_INFINIBAND and the
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hardware address length to 20 (earlier proprietary implementations
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masqueraded to the kernel as ethernet interfaces).
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Partitions and P_Keys
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When the IPoIB driver is loaded, it creates one interface for each
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port using the P_Key at index 0. To create an interface with a
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different P_Key, write the desired P_Key into the main interface's
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/sys/class/net/<intf name>/create_child file. For example:
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echo 0x8001 > /sys/class/net/ib0/create_child
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This will create an interface named ib0.8001 with P_Key 0x8001. To
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remove a subinterface, use the "delete_child" file:
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echo 0x8001 > /sys/class/net/ib0/delete_child
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The P_Key for any interface is given by the "pkey" file, and the
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main interface for a subinterface is in "parent."
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Debugging Information
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By compiling the IPoIB driver with CONFIG_INFINIBAND_IPOIB_DEBUG set
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to 'y', tracing messages are compiled into the driver. They are
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turned on by setting the module parameters debug_level and
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mcast_debug_level to 1. These parameters can be controlled at
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runtime through files in /sys/module/ib_ipoib/.
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CONFIG_INFINIBAND_IPOIB_DEBUG also enables files in the debugfs
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virtual filesystem. By mounting this filesystem, for example with
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mount -t debugfs none /sys/kernel/debug
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it is possible to get statistics about multicast groups from the
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files /sys/kernel/debug/ipoib/ib0_mcg and so on.
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The performance impact of this option is negligible, so it
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is safe to enable this option with debug_level set to 0 for normal
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operation.
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CONFIG_INFINIBAND_IPOIB_DEBUG_DATA enables even more debug output in
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the data path when data_debug_level is set to 1. However, even with
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the output disabled, enabling this configuration option will affect
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performance, because it adds tests to the fast path.
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References
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IETF IP over InfiniBand (ipoib) Working Group
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http://ietf.org/html.charters/ipoib-charter.html
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