diff --git a/winsup/cygwin/ChangeLog b/winsup/cygwin/ChangeLog
index 943065ae3..893c35e64 100644
--- a/winsup/cygwin/ChangeLog
+++ b/winsup/cygwin/ChangeLog
@@ -1,3 +1,13 @@
+2007-01-04  Brian Ford  <Brian.Ford@FlightSafety.com>
+	    Corinna Vinschen  <corinna@vinschen.de>
+
+	* fhandler.h (PREFERRED_IO_BLKSIZE): Define as 64K.
+	* fhandler.cc (fhandler_base::fstat): Set st_blksize to
+	PREFERRED_IO_BLKSIZE.
+	* fhandler_disk_file.cc (fhandler_base::fstat_helper): Ditto.
+	* fhandler_mailslot.cc (fhandler_mailslot::fstat): Ditto.
+	* fhandler_raw.cc (fhandler_dev_raw::fstat): Ditto.
+
 2007-01-01  Christopher Faylor  <me@cgf.cx>
 
 	* spawn.cc (spawn_guts): Don't expect synchronization from a non-cygwin
diff --git a/winsup/cygwin/fhandler.cc b/winsup/cygwin/fhandler.cc
index 5070855dd..7c51a6e3d 100644
--- a/winsup/cygwin/fhandler.cc
+++ b/winsup/cygwin/fhandler.cc
@@ -1,7 +1,7 @@
 /* fhandler.cc.  See console.cc for fhandler_console functions.
 
    Copyright 1996, 1997, 1998, 1999, 2000, 2001, 2002, 2003, 2004,
-   2005, 2006 Red Hat, Inc.
+   2005, 2006, 2007 Red Hat, Inc.
 
 This file is part of Cygwin.
 
@@ -1328,7 +1328,7 @@ fhandler_base::fstat (struct __stat64 *buf)
   buf->st_uid = geteuid32 ();
   buf->st_gid = getegid32 ();
   buf->st_nlink = 1;
-  buf->st_blksize = S_BLKSIZE;
+  buf->st_blksize = PREFERRED_IO_BLKSIZE;
   time_as_timestruc_t (&buf->st_ctim);
   buf->st_atim = buf->st_mtim = buf->st_ctim;
   return 0;
diff --git a/winsup/cygwin/fhandler.h b/winsup/cygwin/fhandler.h
index 6e7bf4821..5a294f30a 100644
--- a/winsup/cygwin/fhandler.h
+++ b/winsup/cygwin/fhandler.h
@@ -1,7 +1,7 @@
 /* fhandler.h
 
    Copyright 1996, 1997, 1998, 1999, 2000, 2001, 2002, 2003, 2004,
-   2005, 2006 Red Hat, Inc.
+   2005, 2006, 2007 Red Hat, Inc.
 
 This file is part of Cygwin.
 
@@ -25,6 +25,11 @@ details. */
    both flags are set. */
 #define O_NONBLOCK_MASK (O_NONBLOCK | OLD_O_NDELAY)
 
+/* It appears that 64K is the block size used for buffered I/O on NT.
+   Using this blocksize in read/write calls in the application results
+   in a much better performance than using smaller values. */
+#define PREFERRED_IO_BLKSIZE ((blksize_t) 65536)
+
 extern const char *windows_device_names[];
 extern struct __cygwin_perfile *perfile_table;
 #define __fmode (*(user_data->fmode_ptr))
diff --git a/winsup/cygwin/fhandler_disk_file.cc b/winsup/cygwin/fhandler_disk_file.cc
index d7f4b3d94..15f39e42f 100644
--- a/winsup/cygwin/fhandler_disk_file.cc
+++ b/winsup/cygwin/fhandler_disk_file.cc
@@ -1,7 +1,7 @@
 /* fhandler_disk_file.cc
 
    Copyright 1996, 1997, 1998, 1999, 2000, 2001, 2002, 2003, 2004,
-   2005, 2006 Red Hat, Inc.
+   2005, 2006, 2007 Red Hat, Inc.
 
 This file is part of Cygwin.
 
@@ -436,7 +436,7 @@ fhandler_base::fstat_helper (struct __stat64 *buf,
   else
     buf->st_ino = get_namehash ();
 
-  buf->st_blksize = S_BLKSIZE;
+  buf->st_blksize = PREFERRED_IO_BLKSIZE;
 
   if (nAllocSize >= 0LL)
     /* A successful NtQueryInformationFile returns the allocation size
diff --git a/winsup/cygwin/fhandler_mailslot.cc b/winsup/cygwin/fhandler_mailslot.cc
index 07babd2fd..133df0414 100644
--- a/winsup/cygwin/fhandler_mailslot.cc
+++ b/winsup/cygwin/fhandler_mailslot.cc
@@ -1,6 +1,6 @@
 /* fhandler_mailslot.cc.  See fhandler.h for a description of the fhandler classes.
 
-   Copyright 2005 Red Hat, Inc.
+   Copyright 2005, 2007 Red Hat, Inc.
 
    This file is part of Cygwin.
 
@@ -42,7 +42,7 @@ fhandler_mailslot::fstat (struct __stat64 *buf)
       buf->st_uid = geteuid32 ();
       buf->st_gid = getegid32 ();
       buf->st_nlink = 1;
-      buf->st_blksize = S_BLKSIZE;
+      buf->st_blksize = PREFERRED_IO_BLKSIZE;
       time_as_timestruc_t (&buf->st_ctim);
       buf->st_atim = buf->st_mtim = buf->st_ctim;
     }
diff --git a/winsup/cygwin/fhandler_raw.cc b/winsup/cygwin/fhandler_raw.cc
index 77ee252bc..9478ee788 100644
--- a/winsup/cygwin/fhandler_raw.cc
+++ b/winsup/cygwin/fhandler_raw.cc
@@ -1,6 +1,6 @@
 /* fhandler_raw.cc.  See fhandler.h for a description of the fhandler classes.
 
-   Copyright 1999, 2000, 2001, 2002, 2003, 2004, 2005 Red Hat, Inc.
+   Copyright 1999, 2000, 2001, 2002, 2003, 2004, 2005, 2007 Red Hat, Inc.
 
    This file is part of Cygwin.
 
@@ -55,7 +55,7 @@ fhandler_dev_raw::fstat (struct __stat64 *buf)
       buf->st_uid = geteuid32 ();
       buf->st_gid = getegid32 ();
       buf->st_nlink = 1;
-      buf->st_blksize = S_BLKSIZE;
+      buf->st_blksize = PREFERRED_IO_BLKSIZE;
       time_as_timestruc_t (&buf->st_ctim);
       buf->st_atim = buf->st_mtim = buf->st_ctim;
     }