Verified, prioritized analysis in docs/host-latency-plan.md (multi-agent
investigation + adversarial verification). Lands the two low-risk tiers:
Tier 2B — Linux scheduling hygiene:
- boost_thread_priority now nices the capture/encode (-10) and send (-5)
threads on Linux (setpriority, best-effort; no-op without CAP_SYS_NICE),
and the wrong "gamescope caps the game" doc-comment is corrected.
- CUDA context created with CU_CTX_SCHED_BLOCKING_SYNC (frees a core on the
shared box instead of busy-spinning on completion).
- Copies moved off the default stream onto a per-thread highest-priority
CUDA stream (cuStreamCreateWithPriority, graceful NULL-stream fallback)
with a per-stream sync that no longer blocks on the other worker thread's
in-flight copies. Stream priority is measure-then-keep (NVIDIA Linux may
ignore it); never regresses.
Tier 3A — Windows session tuning (new session_tuning.rs, raw C-ABI FFI,
no-op off Windows): once-per-process 1ms timer + DwmEnableMMCSS + HIGH
priority class; per-thread MMCSS "Games" + keep-display-awake. Wired into
both the native (boost_thread_priority) and GameStream (stream.rs) paths.
We had zero session tuning before (Apollo streaming_will_start parity).
Tier 2A (Linux NV12 convert) is specified but intentionally not landed:
it is colour-correctness-critical and needs A/B validation on a GPU box
with a display (green-screen risk). Builds + clippy + fmt green on Linux.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
Full project rename, decided 2026-06-10:
- Crates/binaries: punktfunk-core / punktfunk-host / punktfunk-client-rs.
- C ABI: punktfunk_* symbols, Punktfunk* types, include/punktfunk_core.h,
PUNKTFUNK_FEATURE_QUIC guard (header regenerated; cbindgen renames updated, incl.
PUNKTFUNK_BTN_*/PUNKTFUNK_AXIS_* wire constants).
- Protocol: punktfunk/1 — control-plane magic LMN1 → PKF1, nonce salt lmn1 → pkf1.
WIRE BREAK: clients must be rebuilt from this revision.
- Env knobs: PUNKTFUNK_VIDEO_SOURCE / PUNKTFUNK_COMPOSITOR / PUNKTFUNK_ZEROCOPY / ….
- Host config dir: ~/.config/punktfunk (the box's dir was migrated in place — the
persistent identity is unchanged, pinned fingerprints stay valid).
- Swift package: PunktfunkKit + PunktfunkCore.xcframework + PunktfunkConnection
(Sources/PunktfunkClient app + tests renamed with it); build-xcframework.sh updated.
- scripts/: 60-punktfunk.rules, punktfunk-host.service; OpenAPI doc regenerated.
Also: scripts/headless/run-headless-kde.sh — full headless Plasma bringup. Root cause of
"desktop but no apps/settings" over the stream: plasmashell launched without
XDG_MENU_PREFIX=plasma-, so the launcher resolved a nonexistent applications.menu and
rendered an empty menu. The script sets the complete KDE session env (menu prefix,
KDE_FULL_SESSION, session version) and rebuilds ksycoca before starting plasmashell.
Gate: 97/97 tests, clippy -D warnings (both feature sets), fmt, C-ABI harness PASS,
zero lumen references left outside .git.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
enricobuehler