diff --git a/docs/Doxyfile.qmake b/docs/Doxyfile.qmake
index d77c43782..b2975c197 100644
--- a/docs/Doxyfile.qmake
+++ b/docs/Doxyfile.qmake
@@ -2121,7 +2121,7 @@ HAVE_DOT               = YES
 # Minimum value: 0, maximum value: 32, default value: 0.
 # This tag requires that the tag HAVE_DOT is set to YES.
 
-DOT_NUM_THREADS        = 0
+DOT_NUM_THREADS        = 2
 
 # When you want a differently looking font in the dot files that doxygen
 # generates you can specify the font name using DOT_FONTNAME. You need to make