Parallel filter scheduler to decrease the latency to spawn a VM in Nova

Nova Filter Scheduler: Filters are defined in nova.conf file and the request passes through this host sequentially to filter all the hosts that matches user request. So time taken is T=f1+f2+f3+.... Instead we can pass each filter through a thread and use fork-join model to pass all the hosts through different threads such that the total time taken to filter the hosts according to multi-threading concept is maximum time taken for execution of filters in threads,ie(T=MAX(f1,f2,f3,f4....etc)). And finally intersecting the list of hosts given by each filter will give the filtered hosts. This is an idea and there are lot of constraints involved.