Earliest eligible virtual deadline first scheduling

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Short description: Dynamic scheduling algorithm

Earliest eligible virtual deadline first (EEVDF) is a dynamic priority proportional share scheduling algorithm for soft real-time systems.[1]

Algorithm

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]

Linux kernel scheduler

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]

See also

References

  1. 1.0 1.1 Erickson, Jeremy P.; Anderson, James H. (September 2, 2022). Handbook of Real-Time Computing. Springer Nature. pp. 233–267. doi:10.1007/978-981-287-251-7_4. https://doi.org/10.1007/978-981-287-251-7_4. 
  2. Stoica, Ion; M. Abdel-Wahab, Hussein (1995). Earliest Eligible Virtual Deadline First : A Flexible and Accurate Mechanism for Proportional Share Resource Allocation (Technical report). CS Dpt., Old Dominion Univ. TR-95-22.
  3. Epema, D. H. J. (November 2, 1998). "Decay-usage scheduling in multiprocessors". ACM Transactions on Computer Systems 16 (4): 367–415. doi:10.1145/292523.292535. https://dl.acm.org/doi/10.1145/292523.292535. 
  4. "EEVDF Scheduler May Be Ready For Landing With Linux 6.6" (in en). https://www.phoronix.com/news/Linux-6.6-EEVDF-Likely. 
  5. "[PATCH 00/10 sched: EEVDF using latency-nice [LWN.net]"]. https://lwn.net/ml/linux-kernel/20230306132521.968182689@infradead.org/. 
  6. "An EEVDF CPU scheduler for Linux [LWN.net"]. https://lwn.net/Articles/925371/. 
  7. "EEVDF Scheduler Merged For Linux 6.6, Intel Hybrid Cluster Scheduling Re-Introduced". https://www.phoronix.com/news/Linux-6.6-EEVDF-Merged.