mckey(1) — Linux manual page


MCKEY(1)                        librdmacm                       MCKEY(1)

NAME         top

       mckey - RDMA CM multicast setup and simple data transfer test.

SYNOPSIS         top

       mckey -m multicast_address [-s] [-b bind_address] [-c connections]
                 [-C message_count] [-S message_size] [-p port_space]
       mckey -m multicast_address -s [-b bind_address] [-c connections]
                 [-C message_count] [-S message_size] [-p port_space]
       mckey -M unmapped_multicast_address -b bind_address [-s] [-c connections]
                 [-C message_count] [-S message_size] [-p port_space]

DESCRIPTION         top

       Establishes a set of RDMA multicast communication paths between
       nodes using the librdmacm, optionally transfers datagrams to
       receiving nodes, then tears down the communication.

OPTIONS         top

       -m multicast_address
              IP multicast address to join.

       -M unmapped_multicast_address
              RDMA transport specific multicast address to join.

       -s     Send datagrams to the multicast group.

       -b bind_address
              The local network address to bind to.

       -c connections
              The number of QPs to join the multicast group.  (default

       -C message_count
              The number of messages to transfer over each connection.
              (default 10)

       -S message_size
              The size of each message transferred, in bytes.  This
              value must be smaller than the MTU of the underlying RDMA
              transport, or an error will occur.  (default 100)

       -o     Join the multicast group as a send-only full-member.
              Otherwise the group is joined as a full-member.

       -l     Prevent multicast message loopback. Other receivers on the
              local system will not receive the multicast messages.
              Otherwise all multicast messages are also send to the host
              they originated from and local listeners (and probably the
              sending process itself) will receive the messages.  -p
              port_space The port space of the datagram communication.
              May be either the RDMA UDP (0x0111) or IPoIB (0x0002) port
              space.  (default RDMA_PS_UDP)

NOTES         top

       Basic usage is to start mckey -m multicast_address on a server
       system, then run mckey -m multicast_address -s on a client

       Unique Infiniband SA assigned multicast GIDs can be retrieved by
       invoking mckey with a zero MGID or IP address.  (Example, -M 0 or
       -m  The assigned address will be displayed to allow
       mckey clients to join the created group.

       Because this test maps RDMA resources to userspace, users must
       ensure that they have available system resources and permissions.
       See the libibverbs README file for additional details.

SEE ALSO         top

       rdma_cm(7), ucmatose(1), udaddy(1), rping(1)

COLOPHON         top

       This page is part of the rdma-core (RDMA Core Userspace Libraries
       and Daemons) project.  Information about the project can be found
       at ⟨⟩.  If you have a bug
       report for this manual page, send it to  This page was obtained from the
       project's upstream Git repository
       ⟨⟩ on 2024-06-14.  (At
       that time, the date of the most recent commit that was found in
       the repository was 2024-06-10.)  If you discover any rendering
       problems in this HTML version of the page, or you believe there
       is a better or more up-to-date source for the page, or you have
       corrections or improvements to the information in this COLOPHON
       (which is not part of the original manual page), send a mail to

librdmacm                      2007-05-15                       MCKEY(1)

Pages that refer to this page: rdma_client(1)rdma_server(1)rdma_xclient(1)rdma_xserver(1)rping(1)ucmatose(1)udaddy(1)rdma_cm(7)