gqa(adr-0065): N3 — GEMM-epilogue accumulate dataflow (O = O.corr + P.V)

Two fixes make the recipe's P.V GEMM fold into the rescaled accumulator: (1) op_log marks the composite gemm record accumulate=True when an 'add' epilogue targets the GEMM's own output; data_executor._execute_gemm then does O = O_existing + a@b instead of overwriting. (2) PE_SCHEDULER records the composite's numeric op at COMPLETION (in _retire_on_done) instead of at dispatch, so the GEMM's t_start sorts AFTER its prologue MATH ops -> it reads the computed P and the rescaled O.

Verified end-to-end (DataExecutor): the full recipe produces O = O_old*corr + P@V matching a numpy flash-attention reference. Suite 816 pass / 3 pre-existing fail.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

src/kernbench/components/builtin/pe_scheduler.py

@@ -165,14 +165,9 @@ class PeSchedulerComponent(ComponentBase):
         from kernbench.components.builtin.pe_types import PipelineContext
 
         yield from self._hazard.admit(env, cmd, pe_txn.done)
-        env.process(self._retire_on_done(env, pe_txn.done, cmd.completion.id))
-
-        # Record the composite as a single numeric op for data-mode replay
-        # (ADR-0027): the tiles model latency; this zero-duration record
-        # carries the matmul (a@b → out) the DataExecutor replays. No-op
-        # without an op_logger (latency-only mode), so latency is unchanged.
-        self._on_process_start(env, cmd)
-        self._on_process_end(env, cmd)
+        # Retire from the hazard tracker AND record the composite's numeric
+        # op — both at completion (see _retire_on_done).
+        env.process(self._retire_on_done(env, pe_txn.done, cmd))
 
         plan = self._generate_plan(cmd)
 
@@ -192,11 +187,20 @@ class PeSchedulerComponent(ComponentBase):
         yield self._pending_feeds.put((plan, ctx))
 
     def _retire_on_done(
-        self, env: simpy.Environment, done_event: Any, completion_id: str,
+        self, env: simpy.Environment, done_event: Any, cmd: Any,
     ) -> Generator:
-        """Retire a composite from the RW hazard tracker on completion."""
+        """On composite completion: retire from the RW hazard tracker AND
+        record its numeric op (ADR-0027 / ADR-0065 N1+N3).
+
+        Recording at completion (not dispatch) gives the composite's GEMM a
+        t_start AFTER its prologue MATH ops, so in data mode it reads their
+        results (P, the rescaled O) instead of stale values. No-op without an
+        op_logger → latency-only mode unchanged.
+        """
         yield done_event
-        self._hazard.retire(completion_id)
+        self._hazard.retire(cmd.completion.id)
+        self._on_process_start(env, cmd)
+        self._on_process_end(env, cmd)
 
     def _feed_loop(self, env: simpy.Environment) -> Generator:
         """Single feeder process: FIFO command ordering (ADR-0014 D6).