ib_read_bw Command

Performs a read bandwidth diagnostic. Issued on the Linux InfiniBand host.

Syntax

ib_read_bw [-p TCP_port][-d device][-i IB_port][-m mtu][-o num][-s size][-a][-t depth][-n iters][-b][-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.

Description

This InfiniBand software command performs a bandwidth 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 bandwidth of the data transfer from the server to the client. The connection uses the Reliable Datagram transport.

Options

The following table describes the options to the ib_read_bw command and their purposes:

Example

The following example shows how to run a diagnostic between a local node client and a remote node server with the ib_read_bw command. First configure the remote node server:

# ib_read_bw
------------------------------------------------------------------
                         RDMA_Read BW Test
Connection type : RC
     local address:  LID 0x01, QPN 0x990406, PSN 0xd5c3ba RKey 0x3682003a VAddr 0x002ad63cb81000
     remote address: LID 0x05, QPN 0x220406, PSN 0xa67d82, RKey 0x2af2043f VAddr 0x002b364ab80000
Mtu : 1024
#

Then run the command on the local node client:

# ib_read_bw 192.168.200.100
------------------------------------------------------------------
                         RDMA_Read BW Test
Connection type : RC
     local address:  LID 0x05, QPN 0x220406, PSN 0xa67d82 RKey 0x2af2043f VAddr 0x002b364ab80000
     remote address: LID 0x01, QPN 0x990406, PSN 0xd5c3ba, RKey 0x3682003a VAddr 0x002ad63cb81000
Mtu : 1024
------------------------------------------------------------------
 #bytes #iterations    BW peak[MB/sec]    BW average[MB/sec] 
 65536        1000             763.28                763.26
------------------------------------------------------------------
#

Related Information

• ib_read_lat Command

• ib_send_bw Command

• ib_write_bw Command