When UPerf is started (pressing option 1), every member receives a blocking start() RPC which takes as long as the test duration (default: 60s).

This means that the start() RPC will add 60s to the average delivery time (see JGRP-2640, or as used in TIME).

Assuming that regular RPCs take a few microseconds to process, adding 60s to the average will distort the average invocation/delivery time.

Solution: use an async RPC