[boost] Lock free condition_variable or using shared_lock

I'm not too familiar with the mechanisms which underlie mutexs and conditionals, which is why I'm asking this question. Is it possible to modify condition_variable so that wait() can be called on shared_lock? The use case would be it is acceptable to release all threads waiting on a condition_variable when notify_all() is called. Using a unique_lock, every thread who wakes up will then have to obtain the lock before proceeding; this being a potential bottleneck. An even more performant alternative to using shared_lock would be with a dummy lock never blocks when dummy_lock.lock() is called. These are things I would like to contribute, but I need would need some guidance and a review of feasibility. Thanks for the help, Kirk