Adding docs for the new accelerated mode

docsite/latest/rst/playbooks2.rst

@@ -937,10 +937,71 @@ Here is an example::
 Note that you must have passphrase-less SSH keys or an ssh-agent configured for this to work, otherwise rsync
 will need to ask for a passphrase.
 
+Accelerated Mode
+````````````````
+
+.. versionadded:: 1.3
+
+While SSH using the ControlPersist feature is quite fast and scalable, there is a certain amount of overhead involved in
+creating connections. This can become something of a bottleneck when the number of hosts grows into the hundreds or 
+thousands. To help overcome this, Ansible offers an accelerated connection option. Accelerated mode can be anywhere from 
+2-6x faster than SSH with ControlPersist enabled, and 10x faster than paramiko.
+
+Accelerated mode works by launching a temporary daemon over SSH. Once the daemon is running, Ansible will connect directly
+to it via a raw socket connection. Ansible secures this communication by using a temporary AES key that is uploaded during
+the SSH connection (this key is different for every host, and is also regenerated every time the daemon is started). By default,
+Ansible will use port 5099 for the accelerated connection, though this is configurable. Once running, the daemon will accept
+connections for 30 minutes, after which time it will terminate itself and need to be restarted over SSH.
+
+Accelerated mode offers several improvments over the original fireball mode:
+
+* No bootstrapping is required, only a single line needs to be added to each play you wish to run in accelerated mode.
+* Support for sudo commands (see below for more details and caveats).
+* Fewer requirements! ZeroMQ is no longer required, nor are there any special packages beyond python-keyczar.
+
+In order to use accelerated mode, simply add `accelerate: true` to your play::
+
+    ---
+    - hosts: all
+      accelerate: true
+      tasks:
+      - name: some task
+        command: echo {{ item }}
+        with_items:
+        - foo
+        - bar
+        - baz
+
+If you wish to change the port Ansible will use for the accelerated connection, just add the `accelerated_port` option::
+
+    ---
+    - hosts: all
+      accelerate: true
+      # default port is 5099
+      accelerate_port: 10000
+
+The `accelerate_port` option can also be specified in the environment variable ACCELERATE_PORT, or in your `ansible.cfg` configuration::
+
+    [accelerate]
+    accelerate_port = 5099
+
+As noted above, accelerated mode also supports running tasks via sudo, however there are two important caveats:
+
+* You must remove requiretty from your sudoers options.
+* Prompting for the sudo password is not yet supported, so the NOPASSWD option is required for commands.
+
+
+
 Fireball Mode
 `````````````
 
-.. versionadded:: 0.8
+.. versionadded:: 0.8 (deprecated as of 1.3)
+
+.. note::
+
+    The following section has been deprecated as of Ansible 1.3 in favor of the accelerated mode described above. This
+    documentation is here for users who may still be using the original fireball connection method only, and should not
+    be used for any new deployments.
 
 Ansible's core connection types of 'local', 'paramiko', and 'ssh' are augmented in version 0.8 and later by a new extra-fast
 connection type called 'fireball'.  It can only be used with playbooks and does require some additional setup