protected int doRampUp() {
			InternalScriptContext grinder = Grinder.grinder;
			if (grinder != null) {
				GrinderProperties properties = grinder.getProperties();
				int rampUpInterval = properties.getInt(GRINDER_PROP_THREAD_INCREMENT_INTERVAL, 0);
				int rampUpStep = properties.getInt(GRINDER_PROP_THREAD_INCREMENT, 0);
				int rampUpInitialThread = properties.getInt(GRINDER_PROP_INITIAL_PROCESS, 0);
				int rampUpInitialSleep = properties.getInt(GRINDER_PROP_INITIAL_THREAD_SLEEP_TIME, 0);
				return doRampUp(rampUpInterval, rampUpStep, rampUpInitialThread, rampUpInitialSleep);
			}
			return 0;
		}
The number of worker threads that have been created but not run to completion.
ngrinder-runtime/src/main/java/net/grinder/engine/process/GrinderProcess.java