User Manual

Rev 2.2-1.0.1
Mellanox Technologies
273
9.5.2 ib_read_lat
ib_read_lat calculates the latency of RDMA read operation of message_size between a pair of
machines. One acts as a server and the other as a client. They perform a ping pong benchmark on
which one side RDMA reads the memory of the other side only after the other side have read his
memory. Each of the sides samples the CPU clock each time they read the other side memory , in
order to calculate latency. Read is available only in RC connection mode (as specified in IB
spec).
Synopsis
Server
ib_read_lat [options]
Client
ib_read_lat [options] <hostname>
Options
The table below lists the various flags of the command.
--report-both Report RX & TX results separately on Bidirectinal BW
tests
--report_gbits Report Max/Average BW of test in Gbit/sec (instead of
MB/sec)
--run_infinitely Run test forever, print results every <duration> seconds
Table 46 - ib_read_lat Flags and Options
Flag Description
-a, --all Run sizes from 2 till 2^23
-c, --connection=<RC/XRC/DC> Connection type RC/XRC/DC (default RC)
-C, --report-cycles Report times in cpu cycle units (default microseconds)
-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)
-h, --help Show this help screen.
-H, --report-histogram Print out all results (default print summary only)
-i, --ib-port=<port> Use port <port> of IB device (default 1)
Table 45 - Additional ib_read_bw Flags and Options
Flag Description