diff --git a/tools/sdbus++-gendir b/tools/sdbus++-gendir
index a38b5fd..4d3252a 100755
--- a/tools/sdbus++-gendir
+++ b/tools/sdbus++-gendir
@@ -41,7 +41,7 @@
 sdbuspp="sdbus++"
 outputdir="."
 listall="no"
-parallel=$(nproc)
+parallel=$(nproc || cat /proc/cpuinfo | grep ^processor | wc -l)
 
 options="$(getopt -o ho:t:j: --long help,list-all,output:,tool:,jobs: -- "$@")"
 eval set -- "$options"