Update config.tcl
diff --git a/openlane/decred_top/config.tcl b/openlane/decred_top/config.tcl
index 9785e37..5589aeb 100644
--- a/openlane/decred_top/config.tcl
+++ b/openlane/decred_top/config.tcl
@@ -35,3 +35,5 @@
 set ::env(GLB_RT_MAXLAYER) 5
 #default is 0
 set ::env(PL_BASIC_PLACEMENT) 0
+
+set ::env(ROUTING_CORES) 8