PyroWave's wavelet encode runs on the GPU's compute/shader cores, so a GPU-bound
game starves it: submit spikes from ~2 ms to ~15 ms under a 95%+ game load and
the stream fps collapses. NVENC is immune (separate encoder ASIC). Two levers to
let the encode get scheduled ahead of the game's rendering:
- Windows process GPU scheduling: D3DKMTSetProcessSchedulingPriorityClass, env
PUNKTFUNK_GPU_PRIORITY = off|above-normal|high (default)|realtime. Best-effort,
once per process, non-fatal on refusal (enc/windows/pyrowave.rs).
- Global-priority Vulkan encode queue (Granite patch 0005): request a
VK_KHR_global_priority queue (PYROWAVE_QUEUE_PRIORITY = off|high|realtime,
default realtime), downgrading REALTIME→HIGH→none on NOT_PERMITTED so a refused
class never regresses the encoder to HEVC.
HONEST STATUS: on an RTX 4090 / Windows / WDDM neither moved the ~15 ms spikes —
the graphics-vs-compute preemption granularity is the wall, not the priority
level. Kept because both are correct, harmless (graceful fallback), and may help
other GPUs/drivers. For a GPU-saturated game the working levers are reducing the
encode's GPU cost (4:2:0/8-bit) or H.265; PyroWave holds full rate on the desktop
and in games that leave the GPU headroom.
Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
