Rethinking congestion control in virtualized datacenters

Abstract

Cloud datacenters are increasingly adopting virtual machines (VMs) to provide elastic cloud services, with TCP being prevalently used for congestion control. In virtualized datacenters, the delays from the hypervisor scheduler can heavily contaminate RTTs sensed by VM senders, preventing TCP from correctly learning the physical network condition. In this dissertation, my direction is to paravirtualize the transport-layer protocol in the guest OS, making it automatically tolerate the virtualized running environment. I then present a preliminary solution, PVTCP, to overcome the distorted congestion information caused by VM scheduling delays.