whatsnew: FileIO.readall performance, os.cpu_count.

And more news item tweaks.

Doc/whatsnew/3.4.rst

@@ -853,6 +853,11 @@ descriptors or a Windows handle:
 * :func:`os.get_inheritable`, :func:`os.set_inheritable`
 * :func:`os.get_handle_inheritable`, :func:`os.set_handle_inheritable`
 
+The :mod:`os` module now provides a :func:`~os.cpu_count` function, analogous to
+the :func:`multiprocessing.cpu_count` function (which is now implemented in
+terms of the new :mod:`os` function).  (Contributed by Trent Nelson, Yogesh
+Chaudhari, Victor Stinner, and Charles-François Natali in :issue:`17914`.)
+
 
 pdb
 ---
@@ -985,6 +990,8 @@ The ``socket.AF_*`` and ``socket.SOCK_*`` constants are now enumeration values
 using the new :mod:`enum` module.  This allows meaningful names to be printed
 during debugging, instead of integer "magic numbers".
 
+The :data:`~socket.AF_LINK` constant is now available on BSD and OSX.
+
 
 sqlite3
 -------
@@ -1341,6 +1348,11 @@ Significant Optimizations
   strings is now significantly faster.  (Contributed by Victor Stinner and
   Antoine Pitrou in :issue:`15596`.)
 
+* A performance issue in :meth:`io.FileIO.readall` has been solved.  This
+  particularly affects Windows, and significantly speeds up the case of piping
+  significant amounts of data through :mod:`subprocess`.  (Contributed
+  by Richard Oudkerk in :issue:`15758`.)
+
 
 
 Deprecated

Misc/NEWS

@@ -2163,9 +2163,11 @@ Library
 
 - Issue #15758: Fix FileIO.readall() so it no longer has O(n**2) complexity.
 
-- Issue #14596: The struct.Struct() objects now use more compact implementation.
+- Issue #14596: The struct.Struct() objects now use a more compact
+  implementation.
 
-- Issue #17981: Closed socket on error in SysLogHandler.
+- Issue #17981: logging's SysLogHandler now closes the socket when it catches
+  socket OSErrors.
 
 - Issue #17964: Fix os.sysconf(): the return type of the C sysconf() function
   is long, not int.
@@ -2186,8 +2188,8 @@ Library
 - Issue #17915: Fix interoperability of xml.sax with file objects returned by
   codecs.open().
 
-- Issue #16601: Restarting iteration over tarfile no more continues from where
-  it left off.  Patch by Michael Birtwell.
+- Issue #16601: Restarting iteration over tarfile really restarts rather
+  than continuing from where it left off.  Patch by Michael Birtwell.
 
 - Issue #17289: The readline module now plays nicer with external modules
   or applications changing the rl_completer_word_break_characters global