GearmanBundle caches all annotations. You can clear or warmup just gearman cache by using custom commands
$ php app/console
gearman
gearman:cache:clear Clears gearman cache data on current environment
gearman:cache:warmup Warms up gearman cache data
Gearman also clear and warmup cache when using Symfony2 cache commands
$ php app/console
cache
cache:clear Clears the cache
cache:warmup Warms up an empty cache