diff -r 0f357cf011d3 Python/marshal.c
--- a/Python/marshal.c	Thu Feb 13 10:49:30 2014 +0200
+++ b/Python/marshal.c	Thu Feb 13 22:23:51 2014 +0200
@@ -62,6 +62,13 @@
 #define WFERR_NESTEDTOODEEP 2
 #define WFERR_NOMEMORY 3
 
+#ifndef NSMALLPOSINTS
+#define NSMALLPOSINTS           257
+#endif
+#ifndef NSMALLNEGINTS
+#define NSMALLNEGINTS           5
+#endif
+
 typedef struct {
     FILE *fp;
     int error;  /* see WFERR_* values */
@@ -75,6 +82,7 @@
     char *buf;
     Py_ssize_t buf_size;
     PyObject *refs; /* dict on marshal, list on unmarshal */
+    unsigned int small_ints_refs[NSMALLNEGINTS + NSMALLPOSINTS];
     int version;
 } WFILE;
 
@@ -235,6 +243,27 @@
     if (Py_REFCNT(v) == 1)
         return 0;
 
+    if (PyLong_CheckExact(v) && Py_SIZE(v) <= 1 && Py_SIZE(v) >= -1) {
+        long ival = PyLong_AS_LONG(v);
+        if (-NSMALLNEGINTS <= ival && ival < NSMALLPOSINTS) {
+            unsigned long w = p->small_ints_refs[ival + NSMALLNEGINTS];
+            if (w != 0) {
+                /* write the reference index to the stream */
+                w--;
+                /* we don't store "long" indices in the dict */
+                assert(0 <= w && w <= 0x7fffffff);
+                w_byte(TYPE_REF, p);
+                w_long(w, p);
+                return 1;
+            } else {
+                Py_ssize_t s = PyDict_Size(p->refs);
+                /* we don't support long indices */
+                if (s < 0x7fffffff) {
+                    p->small_ints_refs[ival + NSMALLNEGINTS] = (unsigned int)s + 1;
+                }
+            }
+        }
+    }
     id = PyLong_FromVoidPtr((void*)v);
     if (id == NULL)
         goto err;
@@ -570,6 +599,7 @@
     if (version >= 3) {
         if ((wf.refs = PyDict_New()) == NULL)
             return; /* caller mush check PyErr_Occurred() */
+        memset(wf.small_ints_refs, 0, sizeof(wf.small_ints_refs));
     } else
         wf.refs = NULL;
     wf.version = version;
@@ -1524,6 +1554,7 @@
     if (version >= 3) {
         if ((wf.refs = PyDict_New()) == NULL)
             return NULL;
+        memset(wf.small_ints_refs, 0, sizeof(wf.small_ints_refs));
     } else
         wf.refs = NULL;
     w_object(x, &wf);