diff --git a/llvm/docs/TestingGuide.rst b/llvm/docs/TestingGuide.rst
--- a/llvm/docs/TestingGuide.rst
+++ b/llvm/docs/TestingGuide.rst
@@ -173,6 +173,17 @@
 
     % llvm-lit ~/llvm/test/CodeGen/ARM
 
+If you want to run lit tests with multiple(N) threads, use:
+
+.. code-block:: bash
+
+    % export LIT_OPTS="-jN"
+
+And then just run check-llvm or any other check- command.
+
+or if you want to make it parmanent for that specific build, pass
+-DLLVM_LIT_ARGS="-sv jN" to CMake.
+
 For more information on using the :program:`lit` tool, see ``llvm-lit --help``
 or the :doc:`lit man page <CommandGuide/lit>`.