If you've been seeing slowness on the scheduler on master, please git pull the latest change : https://github.com/apache/incubator-airflow/pull/1823
This may not solve all of your problems, but it will improve matters. Notes from the commit : "A recent commit has changed the scheduler behavior that it now always stops after a specified period of time. The operation scripts (systemd etc) are not updated for this behavior and many users actually prefer to run the scheduler continously. Secondly the default behavior was changed to not pickup new DAGs immediately, this has lead to confusion with users." -s
