diff --git a/convert.sh b/convert.sh
index 36f9a3a..d012e69 100755
--- a/convert.sh
+++ b/convert.sh
@@ -8,7 +8,8 @@ if [ "$#" = "0" ]; then
 fi
 
 if [ -z "$CONCURRENCY_LEVEL" ]; then
-    CONCURRENCY_LEVEL=1
+#    CONCURRENCY_LEVEL=1
+    CONCURRENCY_LEVEL=`grep "^core id" /proc/cpuinfo | sort -u | wc -l`
 fi
 
 SCRIPTREAL=`realpath "$0"`