The one seam the mechanism history actually implicates: moe_submit's `use`
vector (resolved expert weight/scale slabs) is the only useResource: loop
whose length scales with LRU cache size. With COLI_METAL_RESSET=1, skip that
loop entirely -- the queue-attached MTLResidencySet already guarantees those
buffers are resident -- after resset_flush() commits any pending adds from a
loader burst. Every other useResource: call site (bind_gemv's weight/scale
buffers, attn_decode/layer_decode's Lb/Rb/kvbW/kvbS/inB/pnB/rwB/rbB,
coli_metal_gemm's wb/sb) is left unconditionally unchanged: none of them
scale with cache size, and Lb/Rb carry real GPU-side write traffic ordered by
existing explicit memoryBarrierWithScope: calls, not by useResource:'s hazard
tracking -- narrowing the blast radius rather than removing useResource:
uniformly. Full reasoning, the hazard-tracking tradeoff (residency sets don't
support hazard tracking, per Apple's MTLResidencySet developer documentation
and residency-set adoption guide; the SDK header itself is silent on the
topic), and every judgment call in UNCERTAINTIES: see SUMMARY.md.
Gate off is unaffected: g_resset_enabled is false, so the useResource: loop
runs exactly as before.
monotophic
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