Earliest eligible virtual deadline first (EEVDF) is adynamic priority proportional sharescheduling algorithm forsoft real-time systems.[1]
EEVDF was first described in the 1995 paper "Earliest Eligible Virtual Deadline First : A Flexible and Accurate Mechanism for Proportional Share Resource Allocation" byIon Stoica and Hussein Abdel-Wahab.[2] It uses notions of virtual time, eligible time, virtual requests and virtual deadlines for determining scheduling priority.[1] It has the property that when a job keeps requesting service, the amount of service obtained is always within the maximum quantum size of what it is entitled.[3]
In 2023, Peter Zijlstra proposed replacing theCompletely Fair Scheduler (CFS) in theLinux kernel with an EEVDFprocess scheduler.[4][5] The aim was to remove the need for CFS "latency nice" patches.[6] The EEVDF scheduler replaced CFS in version 6.6 of the Linux kernel.[7]
