The doctrine bundle, the validator and the annotation reader all support caching.

The doctrine bundle supports memcache, apc, array and xcache.

The annotations reader supports file and any mechanism that implements Doctrine\Common\Cache\Cache by providing a service in the configuration.

The validator component only supports apc.

It would be great to be able to define some cache providers in the framework configuration and use them from the configuration of those 3 components.
That would require changing the configuration of the doctrine bundle and the annotation reader and implement a ClassMetadataFactory that would use an instance of Doctrine\Common\Cache\Cache.