Documentation, Support, and Training
Understanding ILOM on the Switch
Administering ILOM (Web Interface)
Understanding Switch-Specific Commands
activate Command (switch-specific)
deactivate Command (switch-specific)
Performs a read latency diagnostic. Issued on the Linux InfiniBand host.
ib_read_lat [-p TCP_port][-d device][-i IB_port][-c RC|UC][-m mtu][-o num][-s size][-a][-t depth][-n iters][-C][-H][-U][-V][-e][-F][IP_address]
where:
TCP_port is the TCP port.
device is the InfiniBand device.
IB_port is the InfiniBand port.
mtu is the size of the MTU.
num is the outstanding reads/atom.
size is the size of the messages.
depth is the size of the TX queue.
iters is the number of message exchanges.
IP_address is the IP address of the remote node host.
This InfiniBand software command performs a latency diagnostic between two nodes in the InfiniBand fabric. The command is dependent upon the Internet Protocol, so the InfiniBand fabric must be configured with Internet Protocol over InfiniBand (IPoIB). The command is a client-server, in that a remote node is configured as a server, while a local node performs as a client.
The command is first run locally on the server. The command is then run again locally on the client, pointing to the IP address of the server. The diagnostic checks the latency of the data transfer from the server to the client. The connection uses the Reliable Datagram transport. Optionally, you can set the connection between the nodes to use Reliable Connection or Unreliable Connection transport.
Note - This command only functions if your InfiniBand fabric is configured with IPoIB.
The following table describes the options to the ib_read_lat command and their purposes:
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The following example shows how to run a diagnostic between a local node client and a remote node server with the ib_read_lat command. First configure the remote node server:
# ib_read_lat ------------------------------------------------------------------ RDMA_Read Latency Test Connection type : RC local address: LID 0x01 QPN 0x9a0406 PSN 0x434b46 RKey 0x3688003a VAddr 0x00000001bfe080 remote address: LID 0x05 QPN 0x230406 PSN 0x99013d RKey 0x2af8043f VAddr 0x000000118a3080 Mtu : 1024 #
Note - The output is not displayed until the local node client issues the respective command.
Then run the command on the local node client:
# ib_read_lat 192.168.200.100 ------------------------------------------------------------------ RDMA_Read Latency Test Connection type : RC local address: LID 0x05 QPN 0x230406 PSN 0x99013d RKey 0x2af8043f VAddr 0x000000118a3080 remote address: LID 0x01 QPN 0x9a0406 PSN 0x434b46 RKey 0x3688003a VAddr 0x00000001bfe080 Mtu : 1024 ------------------------------------------------------------------ #bytes #iterations t_min[usec] t_max[usec] t_typical[usec] 2 1000 9.44 96.39 9.73 ------------------------------------------------------------------ #