KVS: high-efficiency kernel-level virtual switch

Abstract

In clouds, virtual switch (vSwitch) is in charge of packet forwarding between virtual machines (VMs). However, kernel-based vSwitches show throughput degradation for intensive packet processing; this becomes a bottleneck for the network performance of clouds. DPDK-based vSwitch (DPDK vSwitch) [1] has been developed to resolve the performance problem. Although it exhibits high throughput, DPDK vSwitch has two weak points. First, it consumes excessive memory. DPDK vSwitch uses huge page to reduce the number of memory operations, and this design causes high memory consumption even when the traffic is low. According to [2], memory determines the available number of VMs per single physical server. Thus, saving the memory decreases the capital expenditure of clouds. Second, security is another concern of the DPDK vSwitch, because its data plane is exposed to user space with the shared memory [3]. Therefore, the isolation of packets across VMs cannot be guaranteed. To overcome the excessive memory use and security concern, we propose a new kernel-level vSwitch (KVS) based on Linux. KVS do not use huge page nor bypass kernel stack. Instead, KVS applies the following key ideas to enhance the throughput.