diff --git a/tests/mapper.c b/tests/mapper.c
index e69de29b..49ff6204 100644
--- a/tests/mapper.c
+++ b/tests/mapper.c
@@ -0,0 +1,67 @@
+/* libunwind - a platform-independent unwind library
+   Copyright (C) 2004 Hewlett-Packard Co
+	Contributed by David Mosberger-Tang <davidm@hpl.hp.com>
+
+This file is part of libunwind.
+
+Permission is hereby granted, free of charge, to any person obtaining
+a copy of this software and associated documentation files (the
+"Software"), to deal in the Software without restriction, including
+without limitation the rights to use, copy, modify, merge, publish,
+distribute, sublicense, and/or sell copies of the Software, and to
+permit persons to whom the Software is furnished to do so, subject to
+the following conditions:
+
+The above copyright notice and this permission notice shall be
+included in all copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
+NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
+LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
+OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
+WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.  */
+
+/* This program creates lots of mappings such that on Linux the
+   reading of /proc/PID/maps gets very slow.  With proper caching,
+   test-ptrace should still run at acceptable speed once
+   /proc/PID/maps has been scanned.  If the program dies with a
+   SIGALRM, it means it was running unexpectedly slow.  */
+
+#include <signal.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <unistd.h>
+
+#include <sys/mman.h>
+
+int
+main (int argc, char **argv)
+{
+  long n = 0;
+
+  signal (SIGUSR1, SIG_IGN);
+  signal (SIGUSR2, SIG_IGN);
+
+  printf ("Starting mmap test...\n");
+  for (n = 0; n < 30000; ++n)
+    {
+      if (mmap (0, 1, (n & 1) ? PROT_READ : PROT_WRITE,
+		MAP_PRIVATE | MAP_ANONYMOUS | MAP_NORESERVE,
+		-1, 0) == MAP_FAILED)
+	{
+	  printf ("Failed after %ld successful maps\n", n - 1);
+	  exit (0);
+	}
+    }
+
+  alarm (30);	/* die if we don't finish in 30 seconds */
+
+  printf ("Turning on single-stepping...\n");
+  kill (getpid (), SIGUSR1);	/* tell test-ptrace to start single-stepping */
+  printf ("Va bene?\n");
+  kill (getpid (), SIGUSR2);	/* tell test-ptrace to stop single-stepping */
+  printf ("Turned single-stepping off...\n");
+  return 0;
+}
diff --git a/tests/run-ptrace-mapper b/tests/run-ptrace-mapper
index e69de29b..f51cf9a1 100644
--- a/tests/run-ptrace-mapper
+++ b/tests/run-ptrace-mapper
@@ -0,0 +1,2 @@
+#!/bin/sh
+./test-ptrace -c -n -t ./mapper