diff --git a/.gitignore b/.gitignore
index 6669bf0c6..0a1f93b25 100644
--- a/.gitignore
+++ b/.gitignore
@@ -190,6 +190,7 @@
 /test-mktemp
 /test-parse-options
 /test-path-utils
+/test-read-cache
 /test-regex
 /test-revision-walking
 /test-run-command
diff --git a/Makefile b/Makefile
index 0f931a203..b0ee1649a 100644
--- a/Makefile
+++ b/Makefile
@@ -558,6 +558,7 @@ TEST_PROGRAMS_NEED_X += test-mergesort
 TEST_PROGRAMS_NEED_X += test-mktemp
 TEST_PROGRAMS_NEED_X += test-parse-options
 TEST_PROGRAMS_NEED_X += test-path-utils
+TEST_PROGRAMS_NEED_X += test-read-cache
 TEST_PROGRAMS_NEED_X += test-regex
 TEST_PROGRAMS_NEED_X += test-revision-walking
 TEST_PROGRAMS_NEED_X += test-run-command
diff --git a/t/perf/p0002-read-cache.sh b/t/perf/p0002-read-cache.sh
new file mode 100755
index 000000000..9180ae934
--- /dev/null
+++ b/t/perf/p0002-read-cache.sh
@@ -0,0 +1,14 @@
+#!/bin/sh
+
+test_description="Tests performance of reading the index"
+
+. ./perf-lib.sh
+
+test_perf_default_repo
+
+count=1000
+test_perf "read_cache/discard_cache $count times" "
+	test-read-cache $count
+"
+
+test_done
diff --git a/test-read-cache.c b/test-read-cache.c
new file mode 100644
index 000000000..b25bcf139
--- /dev/null
+++ b/test-read-cache.c
@@ -0,0 +1,13 @@
+#include "cache.h"
+
+int main (int argc, char **argv)
+{
+	int i, cnt = 1;
+	if (argc == 2)
+		cnt = strtol(argv[1], NULL, 0);
+	for (i = 0; i < cnt; i++) {
+		read_cache();
+		discard_cache();
+	}
+	return 0;
+}