[Spec] Unify decode KV-commit bookkeeping across spec-v2 workers (#28754)

python/sglang/srt/managers/scheduler_components/batch_result_processor.py

@@ -558,13 +558,10 @@ class SchedulerBatchResultProcessor:
         for i, req in enumerate(batch.reqs):
             accept_tokens = next_token_ids[i * stride : i * stride + accept_lens[i]]
 
-            if req.is_retracted:
-                # reset_for_retract() already zeroes committed/allocated KV.
+            if req.is_retracted or req.finished():
+                # Nothing to settle: no worker pre-claims the bonus, so
+                # kv_committed_len already holds the committed prefix.
                 pass
-            elif req.finished():
-                if not batch.spec_algorithm.is_dflash():
-                    # EAGLE prepare_for_decode pre-claimed the bonus slot.
-                    req.kv_committed_len -= 1
             else:
                 if req.grammar is not None:
                     # Stop accepting once the grammar terminates, so the
@@ -573,13 +570,9 @@ class SchedulerBatchResultProcessor:
                     # grammar.finished.
                     accept_tokens = self._accept_grammar_tokens(req, accept_tokens)
 
+                # Commit the full accepted run (drafts + bonus).
                 num_accept_tokens = len(accept_tokens)
-                if batch.spec_algorithm.is_dflash():
-                    # DFLASH materialized accepted draft tokens plus the bonus token.
-                    req.kv_committed_len += num_accept_tokens
-                else:
-                    # EAGLE prepare_for_decode pre-claimed the bonus slot.
-                    req.kv_committed_len += num_accept_tokens - 1
+                req.kv_committed_len += num_accept_tokens
                 req.spec_verify_ct += 1
 
                 num_correct_drafts = result.num_correct_drafts_per_req_cpu[i]

python/sglang/srt/session/streaming_session.py

@@ -331,9 +331,15 @@ class StreamingSession(BasePrefixCache):
         finished_len = (
             req.finished_len if req.finished_len is not None else len(req.output_ids)
         )
+        target = len(req.origin_input_ids) + finished_len
         self._trim_overshoot(req, finished_len)
 
         slot.save_from_req(req, is_first=is_first)
+        # Inherit the authoritative finished length on the slot, not the lagging
+        # req clock (under overlap + honest committed the clock lags the in-flight
+        # verify by ~1, which would short-change inheritance). Clamp to allocated
+        # to keep committed <= allocated for prepare_for_decode.
+        slot.kv_committed_len = min(target, slot.kv_allocated_len)
 
         # Update req_nodes to this successfully finished request.
         req.session.finish_req(req)

python/sglang/srt/speculative/eagle_info_v2.py

@@ -47,19 +47,15 @@ class EagleDraftInputV2Mixin:
         num_needed_tokens = 0
         for i, r in enumerate(batch.reqs):
             cur = r.kv_allocated_len
-            # max(cur, ...) clamps so adaptive downswitch (smaller alloc_len_per_decode)
-            # cannot make nxt < cur and corrupt allocator state. kv_committed_len lags
-            # batch.seq_lens by ~1 verify in overlap mode, so we react to adaptive
-            # switches one batch later than a seq_lens-based baseline; the 2*alloc
-            # over-allocation buffer absorbs that lag.
+            # max(cur, ...) clamps so adaptive downswitch cannot make nxt < cur.
+            # kv_committed_len is honest (bonus committed in resolve, not here),
+            # so it lags batch.seq_lens by ~1 verify in overlap; 2*alloc absorbs.
             nxt = max(cur, r.kv_committed_len + double_alloc)
             cur_kv_lens[i] = cur
             nxt_kv_lens[i] = nxt
             num_needed_tokens += nxt - cur
             r.kv_allocated_len = nxt
             r.decode_batch_idx += 1
-            # Pre-claim bonus slot here (like normal decode); resolve subtracts 1.
-            r.kv_committed_len += 1
 
         cur_kv_lens_cpu = torch.tensor(cur_kv_lens, dtype=torch.int32, device="cpu")
         nxt_kv_lens_cpu = torch.tensor(nxt_kv_lens, dtype=torch.int32, device="cpu")

test/registered/unit/managers/test_batch_result_processor_spec_grammar.py

@@ -106,9 +106,8 @@ class TestSpecV2GrammarTruncation(CustomTestCase):
         predict_tokens = proc._resolve_spec_v2_tokens(result, _FakeBatch([req]))
 
         self.assertEqual(predict_tokens, [[101, 102]])
-        # EAGLE commits (retained - 1): prepare_for_decode pre-claimed the bonus
-        # slot, and the dropped suffix is never committed.
-        self.assertEqual(req.kv_committed_len, 2 - 1)
+        # No pre-claim: commit the full retained run (no -1 refund).
+        self.assertEqual(req.kv_committed_len, 2)
 
     def test_resolve_keeps_all_when_grammar_not_terminated(self):
         req = _make_req(terminate_after=99)
@@ -118,7 +117,7 @@ class TestSpecV2GrammarTruncation(CustomTestCase):
         predict_tokens = proc._resolve_spec_v2_tokens(result, _FakeBatch([req]))
 
         self.assertEqual(predict_tokens, [[201, 202, 203]])
-        self.assertEqual(req.kv_committed_len, 3 - 1)
+        self.assertEqual(req.kv_committed_len, 3)
 
 
 if __name__ == "__main__":

test/registered/unit/spec/test_decode_bookkeeping_ownership.py

@@ -55,16 +55,11 @@ _OWNER_SITES = {
     (_SB, "ScheduleBatch.prepare_for_extend", "kv_allocated_len"): 1,
     ("mem_cache/common.py", "alloc_for_extend", "evict"): 1,
     ("mem_cache/common.py", "alloc_for_decode", "evict"): 1,
-    # spec v2: pre-claim in the scheduler-driven mixin, settle in resolve
+    # spec v2: no pre-claim; resolve commits the full accepted run uniformly.
     (*_MIXIN, "decode_batch_idx"): 1,
     (*_MIXIN, "evict"): 1,
-    (*_MIXIN, "kv_committed_len"): 1,
     (*_MIXIN, "kv_allocated_len"): 1,
-    # 3rd resolve mutation: DFLASH settles its full commit_lens here (no
-    # pre-claim in prepare_for_decode, unlike the EAGLE mixin).
-    # Spec grammar truncation commits only the retained (pre-termination) length
-    # here, so the dropped suffix is never over-committed (no later rollback).
-    (*_RESOLVE, "kv_committed_len"): 3,
+    (*_RESOLVE, "kv_committed_len"): 1,
     (*_RESOLVE, "spec_verify_ct"): 1,
     (
         "speculative/dflash_info_v2.py",
@@ -92,6 +87,8 @@ _OWNER_SITES = {
     (_SS, "StreamingSession._trim_overshoot", "kv_committed_len"): 1,
     (_SS, "StreamingSession._trim_overshoot", "kv_allocated_len"): 1,
     (_SS, "StreamingSession.try_cache_finished_req", "kv_allocated_len"): 1,
+    # Inherit the authoritative finished length (not the lagging req clock).
+    (_SS, "StreamingSession.try_cache_finished_req", "kv_committed_len"): 1,
 }