This post is aimed for beginners and explains what is qperf command and supplies few examples.
qperf is a Linux command that 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.
Note: For optimal RDMA performance please use perftest package, that is the formal Open Fabrics performance test package (e.g. ib_send_bw, ib_write_bw ...) - click here for the package.
Two hosts connected back to back or via a switch.
Before you start, make sure there is an IP connectivity on the required link.
Run on one host to be considered as the qperf server:
Run on the second node considered as a qperf client command from this format
# qperf <server-ip-or-hostname> <test>
# qperf 126.96.36.199 tcp_bw tcp_lat
bw = 2634 MB/sec
latency = 7 us
The values that you get depends on the network bandwidth, connectivity and congestion.
More options are available on the main page.