diff --git a/ChangeLog b/ChangeLog
index 5e62415607..95e2c07df5 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -31,6 +31,8 @@
 	__task_terminate would ever return successfully.
 	* sysdeps/mach/hurd/profil.c (special_profil_failure): Move variable
 	to global scope.
+	* sysdeps/mach/pagecopy.h (PAGE_THRESHOLD): Rename to
+	PAGE_COPY_THRESHOLD and set to benchmarked 16384.
 
 2018-01-27  James Clarke  <jrtc27@jrtc27.com>
 
diff --git a/sysdeps/mach/pagecopy.h b/sysdeps/mach/pagecopy.h
index 6285ffb416..8583df4569 100644
--- a/sysdeps/mach/pagecopy.h
+++ b/sysdeps/mach/pagecopy.h
@@ -19,8 +19,8 @@
 #include <mach.h>
 
 /* Threshold at which vm_copy is more efficient than well-optimized copying
-   by words.  This parameter should be tuned as necessary.  */
-#define PAGE_THRESHOLD		(2 * PAGE_SIZE)	/* XXX ? */
+   by words.  */
+#define PAGE_COPY_THRESHOLD		(16384)
 
 #define PAGE_SIZE		__vm_page_size
 #define PAGE_COPY_FWD(dstp, srcp, nbytes_left, nbytes)			      \