Index: src/share/poudriere/common.sh
==================================================================
--- src/share/poudriere/common.sh
+++ src/share/poudriere/common.sh
@@ -6,10 +6,17 @@
 RELDATE=$(sysctl kern.osreldate)
 
 dir_empty() {
 	find $1 -maxdepth 0 -empty
 }
+
+get_freefd() {
+	# get the higher opended fd + 10 (10 being for safety)
+	procstat -hf $$ | awk 'function isnum(x){ return(x==x+0) }
+		isnum($3) && last < $3 { last=$3 }
+		END { print $3 + 10}'
+}
 
 err() {
 	if [ $# -ne 2 ]; then
 		err 1 "err expects 2 arguments: exit_number \"message\""
 	fi
@@ -1461,10 +1468,11 @@
 }
 
 delete_old_pkgs() {
 	[ ! -d ${POUDRIERE}/packages/${MASTERNAME}/All ] && return 0
 	[ -n "$(dir_empty ${POUDRIERE}/packages/${MASTERNAME}/All)" ] && return 0
+	parallel_start
 	for pkg in ${POUDRIERE}/packages/${MASTERNAME}/All/*.${PKG_EXT}; do
 		# Check for non-empty directory with no packages in it
 		[ "${pkg}" = "${POUDRIERE}/packages/${MASTERNAME}/All/*.${PKG_EXT}" ] && break
 		parallel_run "delete_old_pkg ${pkg}"
 	done
@@ -1584,46 +1592,38 @@
 	else
 		echo ${LISTPORTS} | tr ' ' '\n'
 	fi
 }
 
-parallel_stop() {
-	wait
+parallel_exec() {
+	eval "$@"
+	echo >&6
+}
+
+parallel_start() {
+	mkfifo ${MASTERMNT}/poudriere/parallel.pipe
+	exec 6<> ${MASTERMNT}/poudriere/parallel.pipe
+	rm -f ${MASTERMNT}/poudriere/parallel.pipe
+	export NBPARALLEL=0
 }
 
-_reap_children() {
-	local skip_count=${1:-0}
-	PARALLEL_CHILDREN_COUNT=0
-	running_jobs=$(jobs -p) # |wc -l here will always be 0
-	for pid in ${running_jobs}; do
-		PARALLEL_CHILDREN_COUNT=$((PARALLEL_CHILDREN_COUNT + 1))
+parallel_stop() {
+	for j in $(jot ${PARALLEL_JOBS}); do
+		wait
 	done
-	[ ${PARALLEL_CHILDREN_COUNT} -lt ${skip_count} ] && return 0
 
-	# No available slot, try to reap some children to find one
-	for pid in ${running_jobs}; do
-		if ! kill -0 ${pid} 2>/dev/null; then
-			wait ${pid} 2>/dev/null || :
-			PARALLEL_CHILDREN_COUNT=$((PARALLEL_CHILDREN_COUNT - 1))
-		fi
-	done
+	exec 6<&-
+	exec 6>&-
 }
 
 parallel_run() {
 	local cmd="$@"
 
-	while :; do
-		_reap_children ${PARALLEL_JOBS}
-		if [ ${PARALLEL_CHILDREN_COUNT} -lt ${PARALLEL_JOBS} ]; then
-			# Execute the command in the background
-			eval "${cmd} &"
-			return 0
-		fi
-		sleep 0.1
-	done
+	[ ${NBPARALLEL} -eq ${PARALLEL_JOBS} ] && read a <&6
+	[ ${NBPARALLEL} -lt ${PARALLEL_JOBS} ] && NBPARALLEL=$((NBPARALLEL + 1))
 
-	return 0
+	parallel_exec ${fd} $cmd &
 }
 
 # Get all data that make this build env unique,
 # so if the same build is done again,
 # we can use the some of the same cached data
@@ -1670,10 +1670,11 @@
 	:> ${MASTERMNT}/poudriere/ports.ignored
 	:> ${MASTERMNT}/poudriere/ports.skipped
 	build_stats
 
 	bset status "computingdeps:"
+	parallel_start
 	for port in $(listed_ports); do
 		[ -d "${MASTERMNT}/usr/ports/${port}" ] || err 1 "Invalid port origin: ${port}"
 		parallel_run "compute_deps ${port}"
 	done
 	parallel_stop