The scheduler updates for Linux 4.6 introduce the concept of simple waitqueues (swait), NUMA scheduling enhancements, NOHZ performance enhancements, and deadline scheduler enhancements.
Simple waitqueues are "pure waitqueues without any of the more complex features of full-blown waitqueues" while the benefit is less memory overhead and faster performance. With Linux 4.6, swaits are being used in the RCU code and KVM vCPU wake-ups.
One of the NUMA scheduling improvements worth mentioning is this patch for more fairly distributing memory between nodes for resulting in more memory bandwith for each instance and thus greater performance. Details on other scheduler updates for the Linux 4.6 kernel can be found via this pull request.