Reduce redundant TMR WAIT edges with bounded bitmap

docs/dfx/dep-gen.md

@@ -75,6 +75,23 @@ inputs to each submit are captured and the graph is reconstructed afterwards.
   immediately and know to update the annotated mirror.
 - **Output.** `<output_prefix>/deps.json` — strided-Tensor schema with
   `tasks[]`, `tensors[]`, and tensor-annotated `edges[]` (see §4).
+- **Edges are as-constructed, not as-reduced.** Both passes replay the same
+  fanin construction, so `deps.json` records the pre-reduction edge set.
+  The `tensormap_and_ringbuffer` runtime's bounded bitmap transitive
+  reduction (`reduce_wait_edges`, applied when the builder flushes in
+  `submit_task_common`) runs *after* construction and clears the `wait`
+  flag on a direct edge already covered by a WAIT path through the
+  producer's own transitive ancestors. A diamond `A→B→C` + `A→C` still
+  shows `A→C` with its constructed flags. The differential gate is
+  unaffected — both passes replay the same construction. What the
+  reduction changes is the edge's flags: a redundant `WAIT|RETAIN` edge
+  demotes to RETAIN-only and a redundant `WAIT`-only edge drops to
+  `DEP_NONE`, with the entry kept either way, so retention and
+  pin-release accounting are preserved and only readiness enforcement
+  is relaxed.
+  [`wait_reduction_sim`](../../simpler_setup/tools/README.md#wait_reduction_sim)
+  replays the reduction offline over a capture to measure its coverage
+  against the full-DAG upper bound.
 
 ### 2.2 Host orchestration (`host_build_graph`)
 

simpler_setup/tools/README.md

@@ -17,6 +17,7 @@ no repo checkout required.
 - **[hbg_bind_phases](#hbg_bind_phases)** — `host_build_graph` `bind`-stage phases from `bind phase=` log markers → per-phase min/median/max plus the control-plane total
 - **[dump_viewer](#dump_viewer)** — inspect / export args dumps (see [docs/args-dump.md](../../docs/dfx/args-dump.md) for full workflow)
 - **[deps_viewer](#deps_viewer)** — `deps.json` (dep_gen) → text or pan/zoom HTML dependency graph
+- **[wait_reduction_sim](#wait_reduction_sim)** — `deps.json` (dep_gen) → bounded-bitmap WAIT reduction coverage vs the full-DAG upper bound, per BL
 
 For CLIs that allow an omitted input, auto-detection paths
 (`outputs/*/chip_swimlane_records.json`, `outputs/*/args_dump/`) are resolved
@@ -591,6 +592,57 @@ python -m simpler_setup.tools.dump_viewer outputs/<case>_<ts>/args_dump/ --index
 
 ---
 
+## wait_reduction_sim
+
+Measure how many redundant WAIT edges the `tensormap_and_ringbuffer`
+runtime's bounded reachability bitmap reduction would remove from a real
+dependency graph, against the exact full-DAG transitive reduction as the
+upper bound (issue #1376 acceptance #9). Decides the production bitmap
+window (BL) from data instead of guesswork.
+
+### Overview
+
+`wait_reduction_sim` reads the same `deps.json` the
+[`deps_viewer`](#deps_viewer) consumes (edges are as-constructed, i.e.
+pre-reduction, so one capture serves baseline and comparison alike). It
+reconstructs the global submission order from the `tasks[]` record order,
+OR-accumulates edge flags per `(pred, succ)` pair, and runs two models over
+the WAIT subgraph:
+
+- **Full reduction** — exact transitive reachability over the whole DAG:
+  the upper bound any reducer could reach.
+- **Online bitmap** — a faithful mirror of the runtime's
+  `reduce_wait_edges` (frozen per-task `R[t]`, two-pass `direct`/`via`
+  fold, `d > BL` window misses kept) at each requested window size.
+
+The report includes per-BL removal counts, `WAIT|RETAIN → RETAIN` demotions
+vs pure WAIT drops, window and cross-ring misses, the producer→consumer
+submission-distance CDF, and the estimated reduction in readiness fanout
+nodes / dependency-pool entries. `DepGenRecord` does not preserve explicit
+dependency kinds yet (#1827), so removal counts are accurate while the report
+marks affected demote-vs-drop classifications as uncertain.
+
+### Usage
+
+```bash
+# Capture once (dep_gen records pre-construction edges; see docs/dfx/dep-gen.md)
+pytest examples/a5/tensormap_and_ringbuffer/qwen3_14b_decode --platform a5 --enable-dep-gen
+
+# Compare BL=64/128/256 (default) against the upper bound
+python -m simpler_setup.tools.wait_reduction_sim outputs/<case>_<ts>/deps.json
+
+# Machine-readable output, e.g. to diff two captures
+python -m simpler_setup.tools.wait_reduction_sim deps_a.json deps_b.json --json report.json
+```
+
+Reading the output: when `BL=64 removed ≈ upper_bound`, the single-word
+window already saturates the graph's redundancy and larger windows buy
+nothing; when the `pct_pairs_within_window` column is well below 100 for a
+BL, the graph has far-apart producer/consumer pairs that only a wider
+window could cover.
+
+---
+
 ## Shared Configuration
 
 ### Input File Format

simpler_setup/tools/__init__.py

@@ -14,6 +14,7 @@
 - ``sched_overhead_analysis``: scheduler overhead deep-dive
 - ``critical_path``          : chip swimlane critical-path compute/stall analysis
 - ``deps_viewer``           : deps.json -> text or pan/zoom HTML dependency graph
+- ``wait_reduction_sim``   : deps.json -> bounded-bitmap WAIT reduction coverage vs full-DAG bound
 - ``dump_viewer``           : inspect args dumps
 - ``strace_timing``         : per-stage / per-round timing from [STRACE] log markers
 - ``hbg_bind_phases``       : per-phase host_build_graph bind statistics from `bind phase=` markers