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 write latency diagnostic. Issued on the Linux InfiniBand host.
ib_write_lat [-p TCP_port][-d device][-i IB_port][-c RC|UC][-m mtu][-s size][-a][-t depth][-n iters][-I size][-C][-H][-U][-V][-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.
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 client to the server. 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_write_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_write_lat command. First configure the remote node server:
# ib_write_lat ------------------------------------------------------------------ RDMA_Write Latency Test Inline data is used up to 400 bytes message Connection type : RC l ocal address: LID 0x01 QPN 0x9e0406 PSN 0x41c40f RKey 0x36a2003a VAddr 0x0000001fe70002 remote address: LID 0x05 QPN 0x270406 PSN 0x5a66a3 RKey 0x2b12043f VAddr 0x00000018c00002 Mtu : 1024 ------------------------------------------------------------------ #bytes #iterations t_min[usec] t_max[usec] t_typical[usec] 2 1000 4.39 30.41 4.65 ------------------------------------------------------------------ #
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_write_lat 192.168.200.100 ------------------------------------------------------------------ RDMA_Write Latency Test Inline data is used up to 400 bytes message Connection type : RC local address: LID 0x05 QPN 0x270406 PSN 0x5a66a3 RKey 0x2b12043f VAddr 0x00000018c00002 remote address: LID 0x01 QPN 0x9e0406 PSN 0x41c40f RKey 0x36a2003a VAddr 0x0000001fe70002 Mtu : 1024 ------------------------------------------------------------------ #bytes #iterations t_min[usec] t_max[usec] t_typical[usec] 2 1000 4.20 54.50 4.65 ------------------------------------------------------------------ #