preload-index: update GIT_FORCE_PRELOAD_TEST support

diff --git a/t/README b/t/README
index 9b13f6d12e83da0415494fd91728374403fcd815..5670c7aad0ad10dcc55c8a6923b19a362c365776 100644 (file)
--- a/t/README
+++ b/t/README
@@ -327,6 +327,9 @@ GIT_TEST_INDEX_VERSION=<n> exercises the index read/write code path
 for the index version specified.  Can be set to any valid version
 (currently 2, 3, or 4).
 
+GIT_TEST_PRELOAD_INDEX=<boolean> exercises the preload-index code path
+by overriding the minimum number of cache entries required per thread.
+
 Naming Tests
 ------------