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reflection_layout

n constant buffers, each with a structurally rich payload — vectors, matrices, an array of a nested `Light` struct, a nested `Material` struct and a scalar array. This is the only workload with a large, deeply-typed shader *parameter interface* (every other workload's interface is a single RWStructuredBuffer), so it is the one stressor for the parameter binding / layout-assignment engine and — with `-reflection-json` (see the spec's reflection_json flag) — the reflection serializer, the layout/reflection path no other workload covers. Scales by breadth = number of parameter blocks the layout engine must place and reflect. Note: layout is computed during compileInner regardless of the flag (so compileInner is the holistic signal); -reflection-json additionally runs the serializer, which is cheap today but tracked here for regression coverage. Scaling null: n scales parameters; ideal layout cost is O(n).

bucket: reflection_layout  ·  mode: target  ·  flags: -target spirv -emit-spirv-directly

Phase composition vs N (stacked sub-counters)

compileInner split into phase buckets (named leaves + (self) residuals) stacked across the sweep sizes — the top edge is compileInner, so you can see which phase drives the scaling.

reflection_layout — phase composition vs N (v2026.5, median ms) reflection_layout 14.5× over N 30→240 0.0 411 823 30 60 120 240 N reflection_layout — parseTranslationUnit reflection_layout — SemanticChecking reflection_layout — generateIR reflection_layout — frontEndExecute (self) reflection_layout — specializeModule reflection_layout — simplifyIR reflection_layout — linkIR reflection_layout — unrollLoopsInModule reflection_layout — legalizeResourceTypes reflection_layout — legalizeExistentialTypeLayout reflection_layout — performMandatoryEarlyInlining reflection_layout — performForceInlining reflection_layout — linkAndOptimizeIR (self) reflection_layout — generateOutput (self) reflection_layout — compileInner (self) phase buckets parseTranslationUnit SemanticChecking generateIR frontEndExecute (self) specializeModule simplifyIR linkIR unrollLoopsInModule legalizeResourceTypes legalizeExistentialTypeLayout performMandatoryEarlyInlining performForceInlining linkAndOptimizeIR (self) emitEntryPointsSourceFromIR generateOutput (self) compileInner (self)

Scaling analysis

floor-subtracted power-law fit (t − floor) = a·Nk; floor = the minimal workload (fixed per-compile cost), k the global exponent, top-2× the local high-end doubling ratio.

N rangefloor (ms)k (work)fit R²t(Nmin)t(Nmax)top-2×
30–24091.390.995527622.73×

Growth attribution (N=30 → N=240)

compileInner grows by 709 ms across the sweep; the mutually-exclusive phase buckets below partition that growth exactly (no nested-timer double counting). × lin is the same metric as the top-level panels, per bucket: the end point vs a linear expectation anchored to the bucket's share of the minimal floor and fitted on the low-N half — 1.0 = grew exactly linearly, >1 bends up. The super-linearity lives where × lin (and k) are red.

buckett@N=30t@N=240Δ msshare× lin∝Nk
SemanticChecking22349+32846%2.42×1.46
generateOutput (self)798+9113%2.14×1.46
linkAndOptimizeIR (self)474+7010%2.03×1.42
simplifyIR454+507%1.48×1.22
legalizeResourceTypes149+497%4.71×1.92

Also growing (below top-5): legalizeExistentialTypeLayout (+39 ms, 5%), generateIR (+22 ms, 3%), frontEndExecute (self) (+15 ms, 2%).

Near-constant (≤2% of growth each): compileInner (self) (2→14 ms), parseTranslationUnit (1→14 ms), performForceInlining (1→10 ms), linkIR (1→8 ms), specializeModule (1→5 ms), performMandatoryEarlyInlining (0→2 ms), unrollLoopsInModule (0→0 ms).

Sweep numbers (median ms)

NcompileInnerfrontEndExecutegenerateOutput
30523021
601025444
120279137124
240762407340