diff -r ea2f6fd04307 README
--- a/README	Wed Aug 19 20:38:39 2015 -0700
+++ b/README	Sat Aug 29 15:44:03 2015 -0500
@@ -185,6 +185,21 @@
 interpreter has been built.
 
 
+Profile-Guided Optimization
+---------------------------
+
+Recent compilers, such as GCC >= 4.8 and Clang, support profile-guided
+optimization.  You can make the profile-opt target to generate such a
+binary. The profile-opt make target first makes the clean target, then
+compiles Python twice (with suitable compiler flags). In between the
+compilations it profiles the execution of the Python test suite. The second
+compilation uses the profile results to further optimize the generated code.
+
+Because of the extra time it takes to produce a Python binary, this is not
+the default. The profile-opt target should be built when compiling Python
+for distributions or production installation.
+
+
 Troubleshooting
 ---------------