Script to limit the number of running processes to one more than the number of cores. Symlink this script to /usr/local/bin/ named as the binary you want to throttle.

proxy.sh

#!/bin/bash

CMD=$(basename $0)  # command used to call this script
CMD=$(type -a -p $CMD | sed -n 2p) #find the next highest priority

RUNNING=$(grep procs_running /proc/stat|cut -d " " -f 2)
BLOCKED=$(grep procs_blocked /proc/stat|cut -d " " -f 2)
PROCESSLIMIT=$(grep cpu /proc/stat | wc -l)

#Wait for running processes to die down
while [ $RUNNING -gt $PROCESSLIMIT ]; do
sleep 1

RUNNING=$(grep procs_running /proc/stat|cut -d " " -f 2)
BLOCKED=$(grep procs_blocked /proc/stat|cut -d " " -f 2)
PROCESSLIMIT=$(grep cpu /proc/stat | wc -l)

done

exec $CMD $@