Train your team

KRN-210 · Linux Kernel Core

CFS to EEVDF Internals

The fair scheduler in depth, the move to EEVDF, and what changed for latency-sensitive workloads.

Advanced 3 days in person6 half-days online Max 14 in person

Who this course is for

Kernel and performance engineers tuning latency-sensitive services who need to know what the fair scheduler actually does today — including what EEVDF changed and which tuning knobs are gone.

Prerequisites

KRN-201 or strong scheduler backgroundComfort reading kernel/sched/ sourcecgroup v2 basics

Course outline

Day 1 — CFS mechanics

  • vruntime, weights and the nice-to-weight mapping
  • The red-black tree and min_vruntime
  • Sleeper fairness and wakeup preemption
  • Group scheduling and cgroup CPU controllers: cpu.weight, cpu.max
  • Reading scheduler state from /proc and sched debug interfaces

Day 2 — Load tracking and balancing

  • PELT load tracking and its decay behaviour
  • Load balancing across CPUs and scheduling domains
  • NUMA balancing and automatic migration
  • Energy-aware scheduling basics
  • Where balancing goes wrong and how to see it

Day 3 — EEVDF and honest tuning

  • Eligibility, lag and virtual deadlines
  • What EEVDF replaced and why the old heuristics went away
  • Which scheduler sysctls remain, which are gone, and what to use instead
  • Measuring fairness and latency under controlled contention
  • Capstone workshop

Hands-on labs

Labs follow the academy model — 35% principles, 20% guided investigation, 45% engineering studio. Every claim you make in a lab is backed by a trace, a counter or a measurement you captured yourself. How we teach

  1. Lab: observe vruntime and weights under controlled contention and verify the weight ratios you configured
  2. Lab: watch PELT signals through scheduler tracepoints while migrating a load across CPUs
  3. Lab: throttle a service with cgroup cpu.max and measure the resulting latency distribution
  4. Lab: compare CFS vs EEVDF behaviour for a wakeup-heavy workload across two kernel versions
  5. Lab: audit a real system's scheduler sysctls against a current kernel and retire the dead knobs

Capstone project

Take a contended, latency-sensitive workload and make it fair and predictable on a current kernel: cgroup CPU configuration, measured fairness evidence from scheduler traces, latency distributions under load, and a written account of which tunables you changed and which you removed — with trace evidence attached to every claim.

What you leave with

  • A working model of CFS and EEVDF mechanics
  • PELT and load-balance tracing skills
  • cgroup CPU control that does what you expect
  • An up-to-date sysctl map: what exists, what is gone

How it runs

Every course follows the same model: 35% principles, 20% guided investigation, 45% engineering studio. You leave with working code, raw measurements and an evidence-based report — not a certificate of attendance. Read the methodology or see a full sample lesson.

Material is adapted to your kernel version, hardware and workload before a private delivery. For public cohorts, the environment is provided and configured.

Questions

Who is this course for?

Kernel and performance engineers tuning latency-sensitive services who need to know what the fair scheduler actually does today — including what EEVDF changed and which tuning knobs are gone. It sits at advanced level within the Linux Kernel Core track.

What do I need to know already?

Specific prerequisites for this course: KRN-201 or strong scheduler background; Comfort reading kernel/sched/ source; cgroup v2 basics. We confirm levels before the cohort starts and adapt if a group is stronger or weaker than expected.

Can this run privately for my team?

Yes. Any course runs on-site at your offices anywhere, or live online for a distributed team, with labs adapted to your hardware and codebase.

What is the difference between in-person and online?

In person is 3 full days with hardware on your desk, capped at 14. Online is 6 half-day sessions across about two weeks so you can keep working, capped at 20, with remote lab access.

Do you invoice companies?

Yes. Purchase orders are accepted and invoicing is available in USD, EUR, GBP, SAR and CAD.

Upcoming dates

DatesWhereSeatsEarly birdRegular
18 Oct – 20 Oct 20263 full days RiyadhIn person · KAFD Conference Centre 4 of 14 —SAR 9,000
25 Oct – 27 Oct 20263 full days Kuwait CityIn person · Al Hamra Tower 9 of 14 —KWD 740
1 Nov – 3 Nov 20263 full days MuscatIn person · Knowledge Oasis Muscat 4 of 14 —OMR 920
1 Nov – 8 Nov 20266 half-days Gulf bandLive online · 09:00–13:00 GMT+3 14 of 20 —US$1,750
2 Nov – 4 Nov 20263 full days OttawaIn person · Kanata North Tech Park 9 of 14 —CAD 3,260
9 Nov – 11 Nov 20263 full days TorontoIn person · MaRS Discovery District 4 of 14 CAD 2,930until 10 OctCAD 3,260
9 Nov – 16 Nov 20266 half-days Europe bandLive online · 09:00–13:00 CET 3 of 20 US$1,580until 10 OctUS$1,750
16 Nov – 18 Nov 20263 full days LondonIn person · Shoreditch Works 9 of 14 GBP 1,680until 17 OctGBP 1,870
16 Nov – 23 Nov 20266 half-days Americas bandLive online · 13:00–17:00 ET 8 of 20 US$1,580until 17 OctUS$1,750
23 Nov – 25 Nov 20263 full days BerlinIn person · Factory Görlitzer Park 4 of 14 EUR 1,990until 24 OctEUR 2,210

Dates shown for the next few months. If nothing fits, tell us where and when — cohorts are added on demand, and private delivery can be scheduled any week.

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