sshping measure character-echo latency and bandwidth for an ssh
session.

This utility can be used to test the performance of interactive ssh
sessions or scp file transfers. It uses ssh to log into a remote
system, then runs two tests: the first test sends one character at a
time, waiting for each character to be returned while it records the
latency time for each. The second test sends a dummy file over scp to
/dev/null on the remote system.