qperf man page

qperf — Measure RDMA and IP performance


qperf SERVERNODE [Options] Tests


qperf measures bandwidth and latency between two nodes.  It can work over TCP/IP as well as the RDMA transports.  On one of the nodes, qperf is typically run with no arguments designating it the server node.  One may then run qperf on a client node to obtain measurements such as bandwidth, latency and cpu utilization.

In its most basic form, qperf is run on one node in server mode by invoking it with no arguments.  On the other node, it is run with two arguments: the name of the server node followed by the name of the test.  A list of tests can be found in the section, Tests.  A variety of options may also be specified.

One can get more detailed information on qperf by using the --help option.  Below are examples of using the --help option:

   qperf --help examples       Some examples of using qperf
   qperf --help opts           Summary of options
   qperf --help options        Description of options
   qperf --help tests          Short summary and description of tests
   qperf --help TESTNAME       More information on test TESTNAME


In these examples, we first run qperf on a node called myserver in server mode by invoking it with no arguments.  In all the subsequent examples, we run qperf on another node and connect to the server which we assume has a hostname of myserver.

To run a TCP bandwidth and latency test:

qperf myserver tcp_bw tcp_lat

To run a SDP bandwidth test for 10 seconds:

qperf myserver -t 10 sdp_bw

To run a UDP latency test and then cause the server to terminate:

qperf myserver udp_lat quit

To measure the RDMA UD latency and bandwidth:

qperf myserver ud_lat ud_bw

To measure RDMA UC bi-directional bandwidth:

qperf myserver rc_bi_bw

To get a range of TCP latencies with a message size from 1 to 64K

qperf myserver -oo msg_size:1:64K:*2 -vu tcp_lat


-ar, --access_recv OnOff

If OnOff is non-zero, data is accessed once received.  Otherwise, data is ignored.  By default, OnOff is 0.  This can help to mimic some applications.


Cause received data to be accessed.

-ap, --alt_port Port

Set alternate path port. This enables automatic path failover.

-lap, --loc_alt_port Port

Set local alternate path port. This enables automatic path failover.

-rap, --rem_alt_port Port

Set remote alternate path port. This enables automatic path failover.

-ca, --cpu_affinity PN

Set cpu affinity to PN.  CPUs are numbered sequentially from 0.  If PN is "any", any cpu is allowed otherwise the cpu is limited to the one specified.

-lca, --loc_cpu_affinity PN

Set local processor affinity to PN.

-rca, --rem_cpu_affinity PN

Set remote processor affinity to PN.

-f, --flip OnOff

If non-zero, cause sender and receiver to play opposite roles.


Cause sender and receiver to play opposite roles.

-h, --help Topic

Print out information about Topic.  To see the list of topics, type qperf --help

-H, --host Host

Run test between the current node and the qperf running on node Host. This can also be specified as the first non-option argument.

-i, --id Device:Port

Use RDMA Device and Port.

-li, --loc_id Device:Port

Use local RDMA Device and Port.

-ri, --rem_id Device:Port

Use remote RDMA Device and Port.

-lp, --listen_port Port

Set the port we listen on to ListenPort.  This must be set to the same port on both the server and client machines.  The default value is 19765.

-oo, --loop Var:Init:Last:Incr

Run a test multiple times sequencing through a series of values.  Var is the loop variable; Init is the initial value; Last is the value it must not exceed and Incr is the increment.  It is useful to set the --verbose_used (-vu) option in conjunction with this option.

-m, --msg_size Size

Set the message size to Size.  The default value varies by test.  It is assumed that the value is specified in bytes however, a trailing kib or K, mib or M, or gib or G indicates that the size is being specified in kibibytes, mebibytes or gibibytes respectively while a trailing kb or k, mb or m, or gb or g indicates kilobytes, megabytes or gigabytes respectively.

-mt, --mtu_size Size

Set the MTU size.  Only relevant to the RDMA UC/RC tests.  Units are specified in the same manner as the --msg_size option.

-n, --no_msgs N

Set test duration by number of messages sent instead of time.

-cp, --cq_poll OnOff

Turn polling mode on or off.  This is only relevant to the RDMA tests and determines whether they poll or wait on the completion queues. If OnOff is 0, they wait; otherwise they poll.

-lcp, --loc_cq_poll OnOff

Locally turn polling mode on or off.

-rcp, --rem_cq_poll OnOff

Remotely turn polling mode on or off.


Turn polling mode on.


Turn local polling mode on.


Turn remote polling mode on.

-ip, --ip_port Port

Use Port to run the socket tests.  This is different from --listen_port which is used for synchronization.  This is only relevant for the socket tests and refers to the TCP/UDP/SDP/RDS/SCTP port that the test is run on.

-e, --precision Digits

Set the number of significant digits that are used to report results.

-nr, --rd_atomic Max

Set the number of in-flight operations that can be handled for a RDMA read or atomic operation to Max.  This is only relevant to the RDMA Read and Atomic tests.

-lnr, --loc_rd_atomic Max

Set local read/atomic count.

-rnr, --rem_rd_atomic Max

Set remote read/atomic count.

-sl, --service_level SL

Set RDMA service level to SL.  This is only used by the RDMA tests. The service level must be between 0 and 15.  The default service level is 0.

-lsl, --loc_service_level SL

Set local service level.

-rsl, --rem_service_level SL

Set remote service level.

-sb, --sock_buf_size Size

Set the socket buffer size.  This is only relevant to the socket tests.

-lsb, --loc_sock_buf_size Size

Set local socket buffer size.

-rsb, --rem_sock_buf_size Size

Set remote socket buffer size.

-sp, --src_path_bits N

Set source path bits. If the LMC is not zero, this will cause the connection to use a LID with the low order LMC bits set to N.

-lsp, --loc_src_path_bits N

Set local source path bits.

-rsp, --rem_src_path_bits N

Set remote source path bits.

-sr, --static_rate Rate

Force InfiniBand static rate.  Rate can be one of: 2.5, 5, 10, 20, 30, 40, 60, 80, 120, 1xSDR (2.5 Gbps), 1xDDR (5 Gbps), 1xQDR (10 Gbps), 4xSDR (2.5 Gbps), 4xDDR (5 Gbps), 4xQDR (10 Gbps), 8xSDR (2.5 Gbps), 8xDDR (5 Gbps), 8xQDR (10 Gbps).

-lsr, --loc_static_rate

Force local InfiniBand static rate

-rsr, --rem_static_rate

Force remote InfiniBand static rate

-t, --time Time

Set test duration to Time.  Specified in seconds however a trailing m, h or d indicates that the time is specified in minutes, hours or days respectively.

-to, --timeout Time

Set timeout to Time.  This is the timeout used for various things such as exchanging messages.  The default is 5 seconds.

-lto, --loc_timeout Time

Set local timeout to Time.  This may be used on the server to set the timeout when initially exchanging data with each client. However, as soon as we receive the client's parameters, the client's remote timeout will override this parameter.

-rto, --rem_timeout Time

Set remote timeout to Time.

-un, --unify_nodes

Unify the nodes.  Describe them in terms of local and remote rather than send and receive.

-uu, --unify_units

Unify the units that results are shown in.  Uses the lowest common denominator.  Helpful for scripts.

-ub, --use_bits_per_sec

Use bits/sec rather than bytes/sec when displaying networking speed.

-cm, --use_cm OnOff

Use the RDMA Connection Manager (CM) if OnOff is non-zero.  It is necessary to use the CM for iWARP devices.  The default is to establish the connection without using the CM.  This only works for the tests that use the RC transport.


Use RDMA Connection Manager.

-v, --verbose

Provide more detailed output.  Turns on -vc, -vs, -vt and -vu.

-vc, --verbose_conf

Provide information on configuration.

-vs, --verbose_stat

Provide information on statistics.

-vt, --verbose_time

Provide information on timing.

-vu, --verbose_used

Provide information on parameters used.

-vv, --verbose_more

Provide even more detailed output.  Turns on -vvc, -vvs, -vvt and -vvu.

-vvc, --verbose_more_conf

Provide more information on configuration.

-vvs, --verbose_more_stat

Provide more information on statistics.

-vvt, --verbose_more_time

Provide more information on timing.

-vvu, --verbose_more_used

Provide more information on parameters used.

-V, --version

The current version of qperf is printed.

-ws, --wait_server Time

If the server is not ready, continue to try connecting for Time seconds before giving up.  The default is 5 seconds.



Show configuration


Cause the server to quit


RDS streaming one way bandwidth


RDS one way latency


SCTP streaming one way bandwidth


SCTP one way latency


SDP streaming one way bandwidth


SDP one way latency


TCP streaming one way bandwidth


TCP one way latency


UDP streaming one way bandwidth


UDP one way latency


RC streaming two way bandwidth


RC streaming one way bandwidth


RC one way latency


UC streaming two way bandwidth


UC streaming one way bandwidth


UC one way latency


UD streaming two way bandwidth


UD streaming one way bandwidth


UD one way latency


XRC streaming two way bandwidth


XRC streaming one way bandwidth


XRC one way latency


RC RDMA read streaming one way bandwidth


RC RDMA read one way latency


RC RDMA write streaming one way bandwidth


RC RDMA write one way latency


RC RDMA write one way polling latency


UC RDMA write streaming one way bandwidth


UC RDMA write one way latency


UC RDMA write one way polling latency


RC compare and swap messaging rate


RC fetch and add messaging rate


Verify RC compare and swap


Verify RC fetch and add


Written by Johann George.


None of the RDMA tests are available if qperf is compiled without the RDMA libraries.  None of the XRC tests are available if qperf is compiled without the XRC extensions.  The -f option is not yet implemented in many of the tests.


November 2012 qperf User Commands