diff --git a/docs/native_allocator.md b/docs/native_allocator.md
index a97e705..75a1a70 100644
--- a/docs/native_allocator.md
+++ b/docs/native_allocator.md
@@ -140,6 +140,20 @@
 been allocator bugs that cause memory failures when too much virtual
 address space is consumed. For 64 bit executables, this can be ignored.
 
+NOTE: The default native allocator operates differently in an application
+versus command-line tools running in the shell. In order to run the same
+as an application, follow these instructions:
+
+    > adb shell
+    # export MALLOC_USE_APP_DEFAULTS=1
+    # <Run command-line benchmarks>
+
+Running without setting this environment variable can result in different
+performance and even different RSS usage for the benchmarks mentioned below.
+The environment variable has only been available since API level 36.
+Applications using different native allocator defaults than command-line
+tools has been present since API level 26 (Android O).
+
 ### Bionic Benchmarks
 These are the microbenchmarks that are part of the bionic benchmarks suite of
 benchmarks. These benchmarks can be built using this command: