Train your team

KRN-211 · Linux Kernel Core

CPU Isolation & Affinity

Taking CPUs away from the kernel for latency-critical work: isolcpus, nohz_full, RCU offload and the gotchas.

Advanced 2 days in person4 half-days online Max 14 in person

Who this course is for

Engineers building latency-critical systems — trading, telecom, industrial control — who need CPUs genuinely free of kernel interference, and proof rather than hope.

Prerequisites

KRN-201-level scheduling knowledgeLinux administrationA multicore test machine or VM

Course outline

Day 1 — The isolation toolbox

  • isolcpus (domain and managed_irq variants), nohz_full and rcu_nocbs — why they must be combined
  • Housekeeping CPUs and what legitimately still runs there
  • IRQ affinity: /proc/irq/*/smp_affinity and irqbalance policy
  • Kernel thread and workqueue placement
  • taskset and cpuset-based shields

Day 2 — Proof and pitfalls

  • Verifying isolation actually happened: which ticks, interrupts and RCU callbacks remain
  • Measuring jitter with cyclictest-style latency histograms
  • Interaction with containers and cgroup cpusets
  • Managed interrupts and their placement constraints
  • The common misconfigurations that silently undo isolation

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: configure isolcpus/nohz_full/rcu_nocbs on a test machine and enumerate everything that still runs on the isolated cores
  2. Lab: steer IRQs away from hot CPUs and prove the result in /proc/interrupts
  3. Lab: measure jitter on an isolated vs a non-isolated CPU with latency histograms and explain the difference
  4. Lab: reconcile isolation with a container runtime through cpusets and find where the runtime re-adds interference

Capstone project

Produce a verified isolation configuration for a stated latency target: boot parameters plus affinity configuration, an audit of every remaining interference source on the isolated CPUs, jitter histograms before and after, and a re-validation checklist to run after any kernel or container-runtime change.

What you leave with

  • A correct isolation recipe — the three knobs together, not one
  • IRQ and kthread steering practice
  • Jitter measurement you can rerun after any system change
  • Container and cpuset integration patterns that do not leak interference

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?

Engineers building latency-critical systems — trading, telecom, industrial control — who need CPUs genuinely free of kernel interference, and proof rather than hope. 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-level scheduling knowledge; Linux administration; A multicore test machine or VM. 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 2 full days with hardware on your desk, capped at 14. Online is 4 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
25 Oct – 26 Oct 20262 full days RiyadhIn person · KAFD Conference Centre 5 of 14 —SAR 6,000
25 Oct – 26 Oct 20262 full days Kuwait CityIn person · Al Hamra Tower 10 of 14 —KWD 500
1 Nov – 2 Nov 20262 full days MuscatIn person · Knowledge Oasis Muscat 5 of 14 —OMR 620
8 Nov – 11 Nov 20264 half-days Gulf bandLive online · 09:00–13:00 GMT+3 15 of 20 US$1,040until 9 OctUS$1,150
9 Nov – 10 Nov 20262 full days OttawaIn person · Kanata North Tech Park 10 of 14 CAD 1,960until 10 OctCAD 2,180
9 Nov – 10 Nov 20262 full days TorontoIn person · MaRS Discovery District 5 of 14 CAD 1,960until 10 OctCAD 2,180
9 Nov – 12 Nov 20264 half-days Europe bandLive online · 09:00–13:00 CET 4 of 20 US$1,040until 10 OctUS$1,150
16 Nov – 17 Nov 20262 full days LondonIn person · Shoreditch Works 10 of 14 GBP 1,120until 17 OctGBP 1,250
16 Nov – 19 Nov 20264 half-days Americas bandLive online · 13:00–17:00 ET 9 of 20 US$1,040until 17 OctUS$1,150
23 Nov – 24 Nov 20262 full days BerlinIn person · Factory Görlitzer Park 5 of 14 EUR 1,320until 24 OctEUR 1,470

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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