Index: src/poudriere.d/common.sh
==================================================================
--- src/poudriere.d/common.sh
+++ src/poudriere.d/common.sh
@@ -1200,10 +1200,11 @@
 	# Add to cache if not found.
 	if [ -z "${pkgname}" ]; then
 		pkgname=$(injail make -C /usr/ports/${origin} -VPKGNAME)
 		# Make sure this origin did not already exist
 		existing_origin=$(cache_get_origin "${pkgname}")
+		[ "${existing_origin}" = "${origin}" ] && return
 		[ -n "${existing_origin}" ] &&  err 1 "Duplicated origin for ${pkgname}: ${origin} AND ${existing_origin}. Rerun with -D to see which ports are depending on these."
 		echo "${origin} ${pkgname}" >> ${MASTERMNT:-${JAILMNT}}/poudriere/var/cache/origin-pkgname
 	fi
 	echo ${pkgname}
 }
@@ -1212,26 +1213,39 @@
 	[ $# -ne 1 ] && eargs pkgname
 	local pkgname=$1
 
 	awk -v p=${pkgname} '$2 == p { print $1 }' ${MASTERMNT:-${JAILMNT}}/poudriere/var/cache/origin-pkgname
 }
+
+wait_for_slot() {
+	local nbj=0
+	nbj=$(jobs -p | wc -l)
+	while [ ${nbj##* } -ge ${PARALLEL_JOBS} ]; do
+		wait
+	done
+}
 
 # Take optional pkgname to speedup lookup
 compute_deps() {
 	[ $# -lt 1 ] && eargs port
 	[ $# -gt 2 ] && eargs port pkgnme
 	local port=$1
+	mkdir -p ${JAILMNT}/poudriere/locks/
+	mkdir ${JAILMNT}/poudriere/locks/${port%%/*}_${port##*/} 2>/dev/null || return
 	local pkgname="${2:-$(cache_get_pkgname ${port})}"
+	[ -z "${pkgname}" ] && return
+	rmdir ${JAILMNT}/poudriere/locks/${port%%/*}_${port##*/}
 	local dep_pkgname dep_port
 	local pkg_pooldir="${JAILMNT}/poudriere/pool/${pkgname}"
 	[ -d "${pkg_pooldir}" ] && return
 
 	mkdir "${pkg_pooldir}"
 	for dep_port in `list_deps ${port}`; do
 		debug "${port} depends on ${dep_port}"
 		dep_pkgname=$(cache_get_pkgname ${dep_port})
-		compute_deps "${dep_port}" "${dep_pkgname}"
+		wait_for_slot
+		compute_deps "${dep_port}" "${dep_pkgname}" &
 		touch "${pkg_pooldir}/${dep_pkgname}"
 	done
 }
 
 listed_ports() {
@@ -1268,11 +1282,12 @@
 	:> ${JAILMNT}/poudriere/ports.skipped
 	build_stats
 
 	zset status "computingdeps:"
 	listed_ports | while read port; do
-		compute_deps "${port}"
+		wait_for_slot
+		compute_deps "${port}" &
 	done
 
 	zset status "sanity:"
 
 	if [ ${CLEAN_LISTED:-0} -eq 1 ]; then