Merge pull request #2 from ARM-software/added-performancedata-section

Added section for setprop security perf command
diff --git a/README.md b/README.md
index b127423..87fbdb3 100644
--- a/README.md
+++ b/README.md
@@ -18,6 +18,17 @@
 
 ## Using
 
+### Performance data
+
+In order for performance data to be displayed, profiling needs to be enabled on the device.
+Some devices may disable it by default.
+
+Profiling can be enabled via adb:
+
+```
+adb shell setprop security.perf_harden 0
+```
+
 #### Enabling a Counter:
 
 To enable a counter, create either a PMU or Mali counter and then call its start function.