Index: Modules/_pickle.c
===================================================================
--- Modules/_pickle.c	(revision 71084)
+++ Modules/_pickle.c	(working copy)
@@ -1551,6 +1551,62 @@
     return status;
 }
 
+static int
+batch_dict_exact(PicklerObject *self, PyObject *obj)
+{
+    PyObject *key = NULL;
+    PyObject *value = NULL;
+    int i;
+    Py_ssize_t dict_size, ppos = 0;
+
+    const char mark_op = MARK;
+    const char setitem_op = SETITEM;
+    const char setitems_op = SETITEMS;
+
+    assert(obj != NULL);
+    assert(self->proto > 0);
+
+    dict_size = PyDict_Size(obj);
+    if (dict_size == 1) {
+        /* Only one item to save */
+        if (!PyDict_Next(obj, &ppos, &key, &value))
+            return -1;          /* This should never happen. */
+
+        if (save(self, key, 0) < 0)
+            return -1;
+        if (save(self, value, 0) < 0)
+            return -1;
+        if (pickler_write(self, &setitem_op, 1) < 0)
+            return -1;
+
+        return 0;               /* and we're done! */
+    }
+        
+    /* More than one item to save; write them in batches of BATCHSIZE. */
+    do {
+        i = 0;
+        if (pickler_write(self, &mark_op, 1) < 0)
+            return -1;
+        while (PyDict_Next(obj, &ppos, &key, &value)) {
+            if (save(self, key, 0) < 0)
+                return -1;
+            if (save(self, value, 0) < 0)
+                return -1;
+            if (++i == BATCHSIZE)
+                break;
+        }
+        if (pickler_write(self, &setitems_op, 1) < 0)
+            return -1;
+        if (Py_SIZE(obj) != dict_size) {
+            PyErr_Format(PyExc_RuntimeError,
+                         "dictionary changed size during iteration");
+            return -1;
+        }
+    } while (i == BATCHSIZE);
+
+    return 0;
+}
+
 /* iter is an iterator giving (key, value) pairs, and we batch up chunks of
  *     MARK key value ... key value SETITEMS
  * opcode sequences.  Calling code should have arranged to first create an
@@ -1687,7 +1743,6 @@
 static int
 save_dict(PicklerObject *self, PyObject *obj)
 {
-    PyObject *items, *iter;
     char header[3];
     int len;
     int status = 0;
@@ -1717,16 +1772,31 @@
         goto error;
 
     if (len != 0) {
-        /* Save the dict items. */
-        items = PyObject_CallMethod(obj, "items", "()");
-        if (items == NULL)
-            goto error;
-        iter = PyObject_GetIter(items);
-        Py_DECREF(items);
-        if (iter == NULL)
-            goto error;
-        status = batch_dict(self, iter);
-        Py_DECREF(iter);
+        if (PyDict_CheckExact(obj) && self->proto > 0) {
+            /* We can take certain shortcuts if we know this is a dict and
+               not a dict subclass. */
+            if (Py_EnterRecursiveCall(" while pickling an object") == 0) {
+                status = batch_dict_exact(self, obj);
+                Py_LeaveRecursiveCall();
+            }
+        }
+        else {
+            PyObject *items, *iter;
+
+            /* Save the dict items. */
+            items = PyObject_CallMethod(obj, "items", "()");
+            if (items == NULL)
+                goto error;
+            iter = PyObject_GetIter(items);
+            Py_DECREF(items);
+            if (iter == NULL)
+                goto error;
+            if (Py_EnterRecursiveCall(" while pickling an object") == 0) {
+                status = batch_dict(self, iter);
+                Py_LeaveRecursiveCall();
+            }
+            Py_DECREF(iter);
+        }
     }
 
     if (0) {
@@ -2194,6 +2264,8 @@
     PyObject *memo_key = NULL;
     int status = 0;
 
+    assert(obj != NULL);
+
     if (Py_EnterRecursiveCall(" while pickling an object") < 0)
         return -1;