Add memory consumption table.

pep-0393.txt

@@ -226,6 +226,42 @@ discouraged, or scheduled for removal. This is not the intent of this
 PEP; applications that use them will see a performance penalty,
 though. Future versions of Python may consider to remove them.
 
+Performance
+-----------
+
+Performance of this patch must be considered for both memory
+consumption and runtime efficiency. For memory consumption, the
+expectation is that applications that have many large strings will see
+a reduction in memory usage. For small strings, the effects depend on
+the pointer size of the system, and the size of the Py_UNICODE/wchar_t
+type. The following table demonstrates this for various small string
+sizes and platforms.
+
++-------+---------------------------------+----------------+
+|string | Python 3.2                      | This PEP       |
+|size   +----------------+----------------+                |
+|       | 16-bit wchar_t | 32-bit wchar_t |                |
+|       +---------+------+--------+-------+--------+-------+
+|       | 32-bit  |64-bit| 32-bit |64-bit | 32-bit |64-bit |
++-------+---------+------+--------+-------+--------+-------+
+|1      | 40      | 64   | 40     |  64   | 48     | 88    |
++-------+---------+------+--------+-------+--------+-------+
+|2      | 40      | 64   | 48     |  72   | 48     | 88    |
++-------+---------+------+--------+-------+--------+-------+
+|3      | 40      | 64   | 48     |  72   | 48     | 88    |
++-------+---------+------+--------+-------+--------+-------+
+|4      | 48      | 72   | 56     |  80   | 48     | 88    |
++-------+---------+------+--------+-------+--------+-------+
+|5      | 48      | 72   | 56     |  80   | 48     | 88    |
++-------+---------+------+--------+-------+--------+-------+
+|6      | 48      | 72   | 64     |  88   | 48     | 88    |
++-------+---------+------+--------+-------+--------+-------+
+|7      | 48      | 72   | 64     |  88   | 48     | 88    |
++-------+---------+------+--------+-------+--------+-------+
+|8      | 56      | 80   | 72     |  96   | 56     | 88    |
++-------+---------+------+--------+-------+--------+-------+
+
+
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