Document self-hosting.
git-svn-id: svn://svn.valgrind.org/valgrind/trunk@4896 a5019735-40e9-0310-863c-91ae7b9d1cf9
diff --git a/README_DEVELOPERS b/README_DEVELOPERS
index f7cb502..60ee523 100644
--- a/README_DEVELOPERS
+++ b/README_DEVELOPERS
@@ -50,3 +50,26 @@
jump *$eip
+
+Self-hosting
+~~~~~~~~~~~~
+To run Valgrind under Valgrind:
+
+(1) Check out 2 trees, "inner" and "outer". "inner" runs the app
+ directly and is what you will be profiling. "outer" does the
+ profiling.
+
+(2) Configure inner with --enable-inner and build/install as
+ usual.
+
+(3) Configure outer normally and build/install as usual.
+
+(4) Choose a very simple program (date) and try
+
+ outer/.../bin/valgrind --weird-hacks=enable-outer \
+ --tool=cachegrind -v inner/.../bin/valgrind --tool=none -v prog
+
+It's fragile, confusing and slow, but it does work well enough for
+you to get some useful performance data. At the time of writing
+the allocator is not annotated with client requests so Memcheck is
+not as useful as it could be.