Serialization in php: serialize, json, bson

I chose serialization functions for db - bson. Faster serialize> 1.5 times, json - 3. Yes, and the result is less than all the others.
You can find it in the extension for MongoDB.
Results further.

For each iteration, an array and an object created from the array were processed. strlen1 and strlen2 are the lengths of the resulting strings, respectively.
array (
  '_all' => 
  array (
    'time' => 17.71448302269,
    'N' => 40000,
  ),
  'serialize' => 
  array (
    'time' => 3.4848301410675,
    'strlen1' => 1087,
    'strlen2' => 1168,
  ),
  'json' => 
  array (
    'time' => 6.2529139518738,
    'strlen1' => 950,
    'strlen2' => 966,
  ),
  'json_unesc' => 
  array (
    'time' => 6.0889739990234,
    'strlen1' => 950,
    'strlen2' => 966,
  ),
  'bson' => 
  array (
    'time' => 1.8876740932465,
    'strlen1' => 884,
    'strlen2' => 884,
  ),
)



UPD: Sequential serialization and deserialization were tested.
igbinary is already here:
  'igbinary' => 
  array (
    'time' => 4.2307059764862,
    'strlen1' => 702,
    'strlen2' => 724,
  ),


UPD: msgpack is already without numbers, but it is more interesting. Little. 15% faster than bson in serialization, and in size between bson and igbinary. But anpack is 2 times slower, totaling 2x almost 1.5 times slower. Pros - implementations for many languages.