[jfpaardoo]

What this changes

Fixes #639.

On Windows, plat_cpu_placement() enabled one logical processor per physical core by default for systems with SMT and 4+ physical cores (plat_one_per_core_default). On heterogeneous/hybrid architectures (Intel 12th/13th/14th Gen, Core Ultra, and AMD hybrid architectures with P-cores and E-cores), this truncated the process affinity mask by masking out the second SMT thread on every P-core while keeping all E-cores intact (e.g. an 8-core / 12-thread i5-12450H had threads 1, 3, 5, 7 disabled, leaving only 4 P-threads and 4 E-threads).

Because Savage Wind runs multiple active threads (guest main thread, job workers, audio, file streaming, NVN queue/render thread, Vulkan recorder, present thread, plus graphics driver submission/compiler threads), halving the available P-core execution slots starved the system and forced Windows Thread Director to spill latency-critical threads (the main game thread and render queue) onto low-clock, lower-IPC E-cores. When running on E-cores, frame rate plummeted from 60 FPS down to 40-45 FPS randomly until threads were migrated back.

This change:

1. Detects hybrid architectures in plat_cpu_placement() by comparing EfficiencyClass across RelationProcessorCore records. When min_eff != max_eff, it keeps all logical processors enabled by default (while still allowing explicit override via SAVAGEWIND_ONE_PER_CORE=1).
2. Introduces plat_thread_elevate(), setting THREAD_PRIORITY_ABOVE_NORMAL on Windows for the three critical path threads of frame generation: the guest main thread (KThread id == 1), the NVN render queue thread (queue_thread), and the Vulkan packet recorder thread (run). This ensures Windows Thread Director preferentially schedules the critical path on high-performance P-cores even during heavy bursts of worker activity (such as rune effects, teleporting, or asset streaming).

How it was tested

• Build verification: make runtime-objs -j8 compiled with 0 warnings or errors under MSYS2 UCRT64 / Clang on Windows 11.
• Subsystem test suite:
  • make test-pc-controls: PASS
  • make test-actions: PASS
  • python3 tools/i18n_check.py: PASS
  • git diff --check: PASS
• Verified [cpu] logging on Windows outputs whether hybrid architecture is detected and confirms that all logical processors are retained when P/E cores are present.

Checklist

• Based on the latest test and opened against test
• Built and run locally, and checked in the game
• No game files, keys, firmware, generated game code or save files in the changes

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