[None][test] Enable session prefetch for all test stages

tests/test_common/session_prefetcher.py

@@ -40,12 +40,10 @@
 — the two layers compose: reuse covers the steady state, prefetch covers the
 misses.
 
-Rollout: currently in a CANARY phase (reviewer request) — with no explicit
-setting the plugin is active only on the stage groups in
-``_CANARY_STAGE_PREFIXES`` (CI exports the stage name as ``stageName``).
-``TRTLLM_TEST_PREFETCH_SESSION=1``/``0`` overrides in either direction and
-remains the permanent kill switch. Suites that never import tensorrt_llm's
-executor modules pay nothing — not even the tensorrt_llm import.
+Enabled by default; ``TRTLLM_TEST_PREFETCH_SESSION=0`` disables BOTH pool
+prefetch and weight warming (one kill switch for the whole plugin). Suites
+that never import tensorrt_llm's executor modules pay nothing — not even
+the tensorrt_llm import.
 """
 
 import glob
@@ -72,17 +70,6 @@
     "tensorrt_llm.llmapi.llm",
 )
 
-# Canary rollout stage GROUPS (one multi-GPU LLM-dense, one single-GPU
-# LLM-dense). Prefixes, not exact names: the numbered shard suffix (-1/-2/…)
-# is assigned by dynamic load balancing and cannot be targeted stably.
-# Graduation plan: after a week of clean canary runs (zero failures
-# attributed to the plugin, healthy session-summary counters) this gate is
-# removed and the plugin returns to enabled-by-default.
-_CANARY_STAGE_PREFIXES = (
-    "DGX_H100-4_GPUs-PyTorch-DeepSeek",
-    "A10-PyTorch",
-)
-
 
 def _reuse_layer_active() -> bool:
     """True when the MPI session-reuse layer owns the pool-creation seams.
@@ -280,17 +267,12 @@ def enabled(self) -> bool:
         # pool plus a spare. Disable in xdist workers.
         if os.environ.get("PYTEST_XDIST_WORKER"):
             return False
-        explicit = os.environ.get("TRTLLM_TEST_PREFETCH_SESSION")
-        if explicit is not None:
-            return explicit.lower() in ("1", "true", "yes", "on")
-        # Canary rollout (reviewer request): with no explicit setting, enable
-        # only on the canary stage GROUPS. CI exports the stage name as
-        # ``stageName``; prefix matching covers dynamically numbered shards
-        # (per-shard targeting is impossible — the split is rebalanced as the
-        # test list changes). Everywhere else (including runs without a
-        # stageName) the plugin stays off until the canary graduates.
-        stage = os.environ.get("stageName", "")
-        return any(stage.startswith(p) for p in _CANARY_STAGE_PREFIXES)
+        return os.environ.get("TRTLLM_TEST_PREFETCH_SESSION", "1").lower() in (
+            "1",
+            "true",
+            "yes",
+            "on",
+        )
 
     @staticmethod
     def _next_model_map(items):

tests/unittest/llmapi/test_session_prefetcher.py

@@ -83,34 +83,32 @@ def _arm(prefetcher, pool, spec=4):
     prefetcher._publish(spec, pool, session_prefetcher._spawn_snapshot(), prefetcher._build_gen)
 
 
-def test_canary_enabled_on_canary_stage_groups(monkeypatch):
-    # Canary phase: with no explicit setting, active only on the canary
-    # stage groups; prefix match covers dynamically numbered shards.
+@pytest.mark.parametrize(
+    "stage_name",
+    [
+        None,
+        "A10-PyTorch-2",
+        "DGX_H100-4_GPUs-PyTorch-DeepSeek-1",
+        "DGX_B200-PyTorch-4",
+        "Any-Future-Stage",
+    ],
+)
+def test_enabled_by_default_in_all_stages(monkeypatch, stage_name):
     monkeypatch.delenv("TRTLLM_TEST_PREFETCH_SESSION", raising=False)
     monkeypatch.delenv("PYTEST_XDIST_WORKER", raising=False)
-    monkeypatch.setenv("stageName", "A10-PyTorch-2")
-    assert SessionPrefetcher().enabled
-    monkeypatch.setenv("stageName", "DGX_H100-4_GPUs-PyTorch-DeepSeek-1")
+    if stage_name is None:
+        monkeypatch.delenv("stageName", raising=False)
+    else:
+        monkeypatch.setenv("stageName", stage_name)
     assert SessionPrefetcher().enabled
 
 
-def test_canary_disabled_elsewhere(monkeypatch):
-    monkeypatch.delenv("TRTLLM_TEST_PREFETCH_SESSION", raising=False)
+def test_explicit_env_overrides_default(monkeypatch):
     monkeypatch.delenv("PYTEST_XDIST_WORKER", raising=False)
-    monkeypatch.setenv("stageName", "DGX_B200-PyTorch-4")
-    assert not SessionPrefetcher().enabled
-    monkeypatch.delenv("stageName", raising=False)  # local run, no stage
+    monkeypatch.setenv("TRTLLM_TEST_PREFETCH_SESSION", "0")
     assert not SessionPrefetcher().enabled
-
-
-def test_explicit_env_overrides_canary_gate(monkeypatch):
-    monkeypatch.delenv("PYTEST_XDIST_WORKER", raising=False)
-    monkeypatch.setenv("stageName", "DGX_B200-PyTorch-4")  # not a canary stage
     monkeypatch.setenv("TRTLLM_TEST_PREFETCH_SESSION", "1")
-    assert SessionPrefetcher().enabled  # manual opt-in anywhere
-    monkeypatch.setenv("stageName", "A10-PyTorch-1")  # canary stage
-    monkeypatch.setenv("TRTLLM_TEST_PREFETCH_SESSION", "0")
-    assert not SessionPrefetcher().enabled  # kill switch beats the canary
+    assert SessionPrefetcher().enabled
 
 
 def test_disabled_is_noop(monkeypatch):