diff -r 0259c2c555fb Lib/shutil.py
--- a/Lib/shutil.py	Fri Dec 04 14:52:07 2015 -0800
+++ b/Lib/shutil.py	Sat Dec 05 22:36:56 2015 +0100
@@ -87,6 +87,40 @@
     return (os.path.normcase(os.path.abspath(src)) ==
             os.path.normcase(os.path.abspath(dst)))
 
+if hasattr(os, 'sendfile'):
+    # errnos sendfile can set if not supported on the system
+    _sendfile_err_codes = {code for code, name in errno.errorcode.items() \
+                              if name in ('EINVAL', 'ENOSYS', 'ENOTSUP',
+                                          'EBADF', 'ENOTSOCK', 'EOPNOTSUPP')}
+
+    def _copyfile_sendfile(fsrc, fdst):
+        """Copy data from fsrc to fdst using sendfile, return True if success. """
+        status = False
+        max_bcount = 2 ** 31 - 1
+        bcount = max_bcount
+        offset = 0
+        fdstno = fdst.fileno()
+        fsrcno = fsrc.fileno()
+
+        try:
+            while bcount > 0:
+                bcount = os.sendfile(fdstno, fsrcno, offset, max_bcount)
+                offset += bcount
+            status = True
+        except OSError as e:
+            if e.errno in _sendfile_err_codes:
+                # sendfile is not supported or does not support classic
+                # files (only sockets)
+                pass
+            else:
+                raise
+
+        return status
+
+else:
+    def _copyfile_sendfile(*args, **kwargs):
+        return False
+
 def copyfile(src, dst, *, follow_symlinks=True):
     """Copy data from src to dst.
 
@@ -111,8 +145,10 @@
     if not follow_symlinks and os.path.islink(src):
         os.symlink(os.readlink(src), dst)
     else:
-        with open(src, 'rb') as fsrc:
-            with open(dst, 'wb') as fdst:
+        with open(src, 'rb') as fsrc, open(dst, 'wb') as fdst:
+            # Try to use os.sendfile if available for performance
+            if not _copyfile_sendfile(fsrc, fdst):
+                # sendfile is not available or failed, fallback to copyfileobj
                 copyfileobj(fsrc, fdst)
     return dst
 
diff -r 0259c2c555fb Lib/test/test_shutil.py
--- a/Lib/test/test_shutil.py	Fri Dec 04 14:52:07 2015 -0800
+++ b/Lib/test/test_shutil.py	Sat Dec 05 22:36:56 2015 +0100
@@ -604,6 +604,39 @@
         shutil.copyfile(link, dst)
         self.assertFalse(os.path.islink(dst))
 
+    @unittest.skipUnless(support.is_resource_enabled('largefile'),
+                         'test requires >4GB file support')
+    def test_copyfile_hugefile(self):
+        tmp_dir = self.mkdtemp()
+        src_path = os.path.join(tmp_dir, "src")
+        # Create a > 4GB file with non trivial content
+        chunk_size = 2 ** 14
+        with open(src_path, "wb") as src_file:
+            for offset in range(0, 2 ** 32 + chunk_size + 1, chunk_size):
+                # Generate and write a unique data chunk
+                chunk = str(offset).encode("ascii")
+                chunk = chunk + b"\x00" * (chunk_size - len(chunk))
+                src_file.write(chunk)
+        dst_path = os.path.join(tmp_dir, "dst")
+        try:
+            shutil.copyfile(src_path, dst_path)
+        except OSError as e:
+            if e.errno != getattr(errno, 'ENOSPC', -1):
+                raise
+            self.skipTest("not enough space left")
+        except OverflowError:
+            self.skipTest("no large file support, or not enough space left")
+        self.assertTrue(os.path.isfile(dst_path))
+        # Compare files
+        with open(src_path, "rb") as src_file, \
+                open(dst_path, "rb") as dst_file:
+            while True:
+                src_chunk = src_file.read(chunk_size)
+                dst_chunk = dst_file.read(chunk_size)
+                self.assertEqual(src_chunk, dst_chunk)
+                if not src_chunk:
+                    break
+
     def test_rmtree_uses_safe_fd_version_if_available(self):
         _use_fd_functions = ({os.open, os.stat, os.unlink, os.rmdir} <=
                              os.supports_dir_fd and