Keep the parallel execution pipes full as much as possible.

crup-runner.sh

+#!/bin/bash
+
+if [ -z "$*" ]; then
+  exit 0
+fi
+set -o pipefail
+dir="$1"
+solution="${1%%/*}"
+cd "$solution"
+if [ "$solution" = "$1" ]; then
+  shift
+  $@ | sed "s/^/[$solution] /g" 1>&2
+  if [ $? -ne 0 ]; then
+    exit $?
+  fi
+  "$GIT_EXE" submodule --quiet sync
+  "$GIT_EXE" ls-files -s | grep ^160000 | awk '{print $4}' |
+  sed "s/^/$solution\//g"
+  status=$?
+else
+  submodule="${1#*/}"
+  echo "[$solution] updating $submodule ..."
+  "$GIT_EXE" submodule update --quiet --init "$submodule" |
+  ( grep -v '^Skipping submodule' || true ) | sed "s|^|[$1] |g"
+  status=$?
+  if [ "$status" -ne "0" ]; then
+    echo "[$solution] FAILED to update $submodule"
+  fi
+fi
+exit $status