User Manual

Rev 2.2-1.0.1
Mellanox Technologies
271
9.5 Performance Utilities
The performance utilities described in this chapter are intended to be used as a performance
micro-benchmark.
9.5.1 ib_read_bw
ib_read_bw calculates the BW of RDMA read between a pair of machines. One acts as a server
and the other as a client. The client RDMA reads the server memory and calculate the BW by
sampling the CPU each time it receive a successful completion. The test supports features such as
Bidirectional, in which they both RDMA read from each other memory's at the same time,
change of mtu size, tx size, number of iteration, message size and more. Read is available only in
RC connection mode (as specified in IB spec).
Synopsis
Server
ib_read_bw [options]
Client
ib_read_bw [options] <hostname>
Options
The table below lists the various flags of the command.
Table 44 - ib_read_bw Flags and Options
Flag Description
-a, --all Run sizes from 2 till 2^23
-b, --bidirectional Measure bidirectional bandwidth (default unidirectional)
-c, --connection=<RC/XRC/DC> Connection type RC/XRC/DC (default RC)
-d, --ib-dev=<dev> Use IB device <dev> (default first device found)
-D, --duration Run test for a customized period of seconds.
-e, --events Sleep on CQ events (default poll)
-f, --margin Measure results within margins. (default=2sec)
-F, --CPU-freq Do not fail even if cpufreq_ondemand module is loaded
-h, --help Show this help screen.
-i, --ib-port=<port> Use port <port> of IB device (default 1)
-l, --post_list=<list size> Post list of WQEs of <list size> size (instead of single
post)
-m, --mtu=<mtu> MTU size : 256 - 4096 (default port mtu)
-n, --iters=<iters> Number of exchanges (at least 5, default 1000)