Earliest eligible virtual deadline first (EEVDF) is a dynamic priority proportional share scheduling algorithm for soft 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" by Ion 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 the Completely Fair Scheduler (CFS) in the Linux kernel with an EEVDF process 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]