Meta is using the Linux scheduler designed for Valve's Steam Deck on its servers

Original Article ↗ Hacker News Discussion ↗

Open source cross‑pollination

  • Thread highlights how Valve’s Steam Deck work (SCX‑LAVD scheduler) is now improving Meta’s server efficiency, and notes the reverse flow (e.g., Meta’s Kyber I/O scheduler helping desktop/SteamOS microstutter).
  • Many see this as “commons” behavior: once code is upstreamed under GPL, it’s no longer “Valve’s thing” or “Meta’s thing.”
  • Some warn against relying on “trickledown” from big firms; corporate priorities can change despite licenses.

Why a handheld scheduler works in hyperscale

  • Commenters are surprised a scheduler tuned for handheld gaming also works for Meta’s servers.
  • Explanation: both gaming and large services have hard latency deadlines (frame times, controller input, voice/video, ad auctions, WhatsApp messaging, etc.), while background work can be delayed.
  • SCX‑LAVD is a latency‑aware scheduler; latency vs throughput is a spectrum, not a simple upgrade path.

Linux scheduling and sched_ext

  • Discussion contrasts the legacy Completely Fair Scheduler (CFS), newer EEVDF, and SCX‑LAVD: each chooses different trade‑offs between fairness, throughput, and latency; none is a universally “strict upgrade.”
  • Linux defaults historically favor throughput/fairness and are hard to tune; at hyperscale, even 0.1% gains justify dedicated kernel engineers.
  • sched_ext (developed at Meta) and BPF‑style mechanisms make it easier to plug in alternative schedulers; SCX implementations live in a shared GitHub repo used by multiple companies.

Valve’s role and contractor model

  • Valve is portrayed as a relatively small, revenue‑dense company that contracts out deep systems work (e.g., Igalia for schedulers, graphics stack, Proton pieces).
  • Igalia is described as a worker‑owned, highly skilled Linux consultancy, seen as a positive example of “company funds OSS” in practice.
  • Several comments argue contracting can work extremely well when scope is tight, expertise is high, and the client remains technically engaged.

Linux ecosystem strengths and weaknesses

  • Many credit Valve (plus earlier Wine/CodeWeavers work) with pushing Linux forward: Proton, DXVK, HDR/VRR on Wayland, Gamescope tools, shader pre‑caching, futex improvements, bcachefs sponsorship.
  • Others stress this builds on decades of volunteer groundwork (Wine, kernel, desktop).
  • Recurrent pain points: desktop Linux UX, accessibility, laptop sleep/hibernate, OOM behavior, hardware/driver quirks, fragmented ABIs and mobile platforms.

Business and ethics angles

  • Meta is criticized for scammy ads and AI misuse but also noted as a major Linux kernel contributor.
  • Valve is praised for technical contributions yet criticized for lootboxes and enabling third‑party gambling around in‑game items; some defend Valve as “least bad,” others call that willful blindness.
  • Side debate on RHEL source availability and GPL obligations, with claims that CentOS Stream effectively exposes the code even if RHEL’s own source distribution is awkward.