# Workloads / Scenarios

Shared workload + scenario types used by **both** the Console runner (custom adaptive measure engine) and the BDN runner (`AcBinaryVsMemPackBenchmark` in the parent folder). Same wire payloads, same options, same round-trip-verify gate → Console and BDN cells are directly comparable.

## Layout

### Contract types

- [`ISerializerBenchmark.cs`](ISerializerBenchmark.cs) — common contract for every (Engine × IoMode × OptionsPreset) row. `Serialize()` / `Deserialize()` hot-path + warmup hooks + `VerifyRoundTrip()` for the pre-warmup correctness gate. Round-trip-only benchmarks (NamedPipe / in-memory Pipe) set `IsRoundTripOnly = true` and let the bench loop skip the Des-phase.
- [`BenchmarkEnums.cs`](BenchmarkEnums.cs) — `BenchmarkEngine` / `BenchmarkIoMode` / `BenchmarkDispatchMode` / `BenchmarkLayer` / `BenchmarkOpMode` / `SerializerSelectionMode` + `ToDisplay()` extensions for the column-friendly rendering used by every output formatter.
- [`BenchmarkOptions.cs`](BenchmarkOptions.cs) — per-engine options-formatting helpers + the cached `AttrFlags` aggregation (assembly-scan of `[AcBinarySerializable]` feature flags) + `GetMemPack(WireMode)` for the wire-mode-aligned MemoryPack-options selection.
- [`RoundTripValidator.cs`](RoundTripValidator.cs) — universal deep-equality oracle via canonical System.Text.Json. Called by every benchmark's `VerifyRoundTrip()` before warmup. AOT-skipped (STJ reflection path incompatible).

### Concrete benchmarks (12 implementations)

**AcBinary** (7 variants — different I/O modes):
- [`AcBinaryBenchmark.cs`](AcBinaryBenchmark.cs) — `Byte[]` API. Headline AcBinary row.
- [`AcBinaryBufferWriterBenchmark.cs`](AcBinaryBufferWriterBenchmark.cs) — pre-allocated, reused `ArrayBufferWriter<byte>`.
- [`AcBinaryFreshBufferWriterBenchmark.cs`](AcBinaryFreshBufferWriterBenchmark.cs) — fresh `ArrayBufferWriter` per call (one-shot scenario, 4 KB chunk).
- [`AcBinaryNamedPipeBenchmark.cs`](AcBinaryNamedPipeBenchmark.cs) — chunked-framed `AsyncPipe` over kernel NamedPipe (long-lived, multi-message, 2-task pipeline).
- [`AcBinaryNamedPipeRawByteArrayBenchmark.cs`](AcBinaryNamedPipeRawByteArrayBenchmark.cs) — raw `byte[]` over kernel NamedPipe (no chunk-framing, Read+Des sequential after Read completes).
- [`AcBinaryInMemoryPipeBenchmark.cs`](AcBinaryInMemoryPipeBenchmark.cs) — chunked-framed `AsyncPipe` over in-memory `System.IO.Pipelines.Pipe` (zero kernel involvement, isolates streaming-framework CPU cost from kernel-pipe transport overhead).
- [`AcBinaryInMemoryRawByteArrayBenchmark.cs`](AcBinaryInMemoryRawByteArrayBenchmark.cs) — raw `byte[]` over in-memory cross-thread handoff (no transport at all, completes the 2×2 [chunked|raw] × [kernel|memory] matrix).

**MemoryPack** (3 variants — apples-to-apples with the AcBinary I/O modes):
- [`MemoryPackBenchmark.cs`](MemoryPackBenchmark.cs) — `Byte[]` API. SOTA baseline.
- [`MemoryPackBufferWriterBenchmark.cs`](MemoryPackBufferWriterBenchmark.cs) — reused `ArrayBufferWriter`.
- [`MemoryPackFreshBufferWriterBenchmark.cs`](MemoryPackFreshBufferWriterBenchmark.cs) — fresh `ArrayBufferWriter` per call.

**Other** (reference comparison, typically disabled in active suite):
- [`MessagePackBenchmark.cs`](MessagePackBenchmark.cs) — JIT-only (AOT-incompatible — v3 StandardResolver falls back to `Activator.CreateInstance` on trimmed closed-generic types).
- [`SystemTextJsonBenchmark.cs`](SystemTextJsonBenchmark.cs) — String I/O mode, reflection-based metadata. Far behind binary serializers on µs/op; useful as a JSON baseline when activated.

## Convention

Every concrete benchmark:

1. Stores the test data graph + serializer options in its ctor and pre-computes a `_serialized` byte array for `SerializedSize` reporting.
2. Implements `Serialize()` / `Deserialize()` as `[MethodImpl(NoInlining)]` hot-paths — the bench loop drives these directly through warmup + adaptive-iter calibration + measurement.
3. Implements `VerifyRoundTrip()` by calling `RoundTripValidator.DeepEqualsViaJson(original, roundTripped)` on the result of a single Ser+Des pass.
4. Round-trip-only variants (NamedPipe / in-memory Pipe) override `IsRoundTripOnly => true`, route the full Ser+wire+Des roundtrip through `Serialize()`, and leave `Deserialize()` as a no-op.

The runner (Console `BenchmarkLoop` or BDN `AcBinaryVsMemPackBenchmark`) creates the appropriate concrete via factory helpers and drives the contract — no scenario-specific knowledge in the runner.
