building/running-tests.md

 # GHC Test framework
 
 
-NOTE: you need Python (any version \>= 1.5 will probably do) in order
-to use the testsuite.
+NOTE: you need GNU make and Python (any version \>= 1.5 will probably do) in order
+to use the testsuite. If you want to run the testsuite in parallel then you need Python 2.5.2 or later.
 
 
 If you have not checked out the test suite, first run:
@@ -73,6 +73,20 @@ To add specific options to the compiler:
 ```
 
 
+To save disk space you can have temporary files deleted after each test:
+
+```wiki
+        make CLEANUP=1
+```
+
+
+If you have python 2.5.2 or later then you can run the testsuite in parallel:
+
+```wiki
+        make THREADS=2
+```
+
+
 For more details, see below.
 
 # Running the testsuite with a compiler other than GHC