[Bugfix] Register VLLM_BATCH_INVARIANT in envs.py to fix spurious unknown env var warning

tests/kernels/attention/test_use_trtllm_attention.py

@@ -55,37 +55,37 @@ def _clear_supports_cache():
 # supports_trtllm_attention
 
 
-@patch("vllm.utils.flashinfer.vllm_is_batch_invariant", return_value=True)
-def test_supports_batch_invariant_disables(_mock):
+@patch("vllm.envs.VLLM_BATCH_INVARIANT", True)
+def test_supports_batch_invariant_disables():
     assert supports_trtllm_attention() is False
 
 
-@patch("vllm.utils.flashinfer.vllm_is_batch_invariant", return_value=False)
+@patch("vllm.envs.VLLM_BATCH_INVARIANT", False)
 @patch(
     "vllm.utils.flashinfer.current_platform.is_device_capability_family",
     return_value=True,
 )
 @patch("vllm.utils.flashinfer.has_nvidia_artifactory", return_value=True)
-def test_supports_sm100_with_artifactory(_art, _cap, _bi):
+def test_supports_sm100_with_artifactory(_art, _cap):
     assert supports_trtllm_attention() is True
 
 
-@patch("vllm.utils.flashinfer.vllm_is_batch_invariant", return_value=False)
+@patch("vllm.envs.VLLM_BATCH_INVARIANT", False)
 @patch(
     "vllm.utils.flashinfer.current_platform.is_device_capability_family",
     return_value=False,
 )
-def test_supports_non_sm100_platform(_cap, _bi):
+def test_supports_non_sm100_platform(_cap):
     assert supports_trtllm_attention() is False
 
 
-@patch("vllm.utils.flashinfer.vllm_is_batch_invariant", return_value=False)
+@patch("vllm.envs.VLLM_BATCH_INVARIANT", False)
 @patch(
     "vllm.utils.flashinfer.current_platform.is_device_capability_family",
     return_value=True,
 )
 @patch("vllm.utils.flashinfer.has_nvidia_artifactory", return_value=False)
-def test_supports_sm100_without_artifactory(_art, _cap, _bi):
+def test_supports_sm100_without_artifactory(_art, _cap):
     assert supports_trtllm_attention() is False
 
 

tests/kernels/moe/test_grouped_topk.py

@@ -8,7 +8,7 @@
 import pytest
 import torch
 
-import vllm.model_executor.layers.batch_invariant as batch_invariant
+import vllm.envs as envs
 from vllm.config import (
     CompilationConfig,
     VllmConfig,
@@ -69,7 +69,7 @@ def test_grouped_topk(
 
     with set_current_vllm_config(vllm_config), monkeypatch.context() as m:
         m.setenv("VLLM_USE_FUSED_MOE_GROUPED_TOPK", "0")
-        m.setattr(batch_invariant, "VLLM_BATCH_INVARIANT", True)
+        m.setattr(envs, "VLLM_BATCH_INVARIANT", True)
         grouped_topk = GroupedTopk(
             topk=topk,
             renormalize=renormalize,

tests/v1/determinism/conftest.py

@@ -2,11 +2,11 @@
 # SPDX-FileCopyrightText: Copyright contributors to the vLLM project
 import pytest
 
-import vllm.model_executor.layers.batch_invariant as batch_invariant
+import vllm.envs as envs
 
 
 @pytest.fixture(autouse=True)
 def enable_batch_invariant_mode(monkeypatch: pytest.MonkeyPatch):
     """Automatically enable batch invariant kernel overrides for all tests."""
-    monkeypatch.setattr(batch_invariant, "VLLM_BATCH_INVARIANT", True)
+    monkeypatch.setattr(envs, "VLLM_BATCH_INVARIANT", True)
     monkeypatch.setenv("VLLM_BATCH_INVARIANT", "1")

tests/v1/determinism/test_batch_invariance.py

@@ -15,7 +15,7 @@
     skip_unsupported,
 )
 
-import vllm.model_executor.layers.batch_invariant as batch_invariant
+import vllm.envs as envs
 from vllm import LLM, SamplingParams
 
 IS_DEVICE_CAPABILITY_BELOW_90 = is_device_capability_below_90()
@@ -173,11 +173,9 @@ def test_logprobs_bitwise_batch_invariance_bs1_vs_bsN(
 
     # For batch invariance, disable custom all-reduce to ensure deterministic
     # all-reduce operations (custom all-reduce may not be deterministic)
-    from vllm.model_executor.layers.batch_invariant import (
-        vllm_is_batch_invariant,
-    )
+    import vllm.envs as envs
 
-    disable_custom_ar = vllm_is_batch_invariant()
+    disable_custom_ar = envs.VLLM_BATCH_INVARIANT
 
     if disable_custom_ar:
         print(f"\n{'=' * 80}")
@@ -454,7 +452,7 @@ def test_logprobs_without_batch_invariance_should_fail(
     """
     # CRITICAL: Disable batch invariance for this test
     monkeypatch.setenv("VLLM_BATCH_INVARIANT", "0")
-    monkeypatch.setattr(batch_invariant, "VLLM_BATCH_INVARIANT", False)
+    monkeypatch.setattr(envs, "VLLM_BATCH_INVARIANT", False)
     seed = int(os.getenv("VLLM_TEST_SEED", "12345"))
     random.seed(seed)
     tp_size = int(os.getenv("VLLM_TEST_TP_SIZE", "1"))
@@ -674,11 +672,9 @@ def test_decode_logprobs_match_prefill_logprobs(
     random.seed(seed)
     tp_size = int(os.getenv("VLLM_TEST_TP_SIZE", "1"))
 
-    from vllm.model_executor.layers.batch_invariant import (
-        vllm_is_batch_invariant,
-    )
+    import vllm.envs as envs
 
-    disable_custom_ar = vllm_is_batch_invariant()
+    disable_custom_ar = envs.VLLM_BATCH_INVARIANT
 
     if disable_custom_ar:
         print(f"\n{'=' * 80}")

vllm/config/parallel.py

@@ -14,9 +14,6 @@
 import vllm.envs as envs
 from vllm.config.utils import config
 from vllm.logger import init_logger
-from vllm.model_executor.layers.batch_invariant import (
-    vllm_is_batch_invariant,
-)
 from vllm.platforms import current_platform
 from vllm.utils.network_utils import get_open_ports_list
 from vllm.utils.torch_utils import cuda_device_count_stateless
@@ -786,7 +783,7 @@ def _verify_args(self) -> Self:
         from vllm.v1.executor import Executor
 
         # Enable batch invariance settings if requested
-        if vllm_is_batch_invariant():
+        if envs.VLLM_BATCH_INVARIANT:
             self.disable_custom_all_reduce = True
 
         if (

vllm/config/vllm.py

@@ -1112,11 +1112,9 @@ def has_blocked_weights():
                     "when cudagraph_mode piecewise cudagraphs is used, "
                     f"cudagraph_mode={self.compilation_config.cudagraph_mode}"
                 )
-        from vllm.model_executor.layers.batch_invariant import vllm_is_batch_invariant
-
         if (
             self.model_config
-            and vllm_is_batch_invariant()
+            and envs.VLLM_BATCH_INVARIANT
             and not self.model_config.disable_cascade_attn
         ):
             self.model_config.disable_cascade_attn = True

vllm/distributed/device_communicators/all_reduce_utils.py

@@ -19,9 +19,6 @@
 import vllm.envs as envs
 from vllm.distributed.device_communicators.cuda_wrapper import CudaRTLibrary
 from vllm.logger import init_logger
-from vllm.model_executor.layers.batch_invariant import (
-    vllm_is_batch_invariant,
-)
 from vllm.utils.system_utils import update_environment_variables
 from vllm.utils.torch_utils import cuda_device_count_stateless
 
@@ -115,7 +112,7 @@ def should_nccl_symm_mem_allreduce(world_size: int, input_tensor: torch.Tensor)
         is_symmetric_memory_enabled,
     )
 
-    if vllm_is_batch_invariant():
+    if envs.VLLM_BATCH_INVARIANT:
         return False
 
     if not is_symmetric_memory_enabled():

vllm/distributed/device_communicators/symm_mem.py

@@ -5,13 +5,11 @@
 import torch.distributed as dist
 from torch.distributed import ProcessGroup
 
+import vllm.envs as envs
 from vllm.distributed.device_communicators.all_reduce_utils import (
     SYMM_MEM_ALL_REDUCE_MAX_SIZES,
 )
 from vllm.logger import init_logger
-from vllm.model_executor.layers.batch_invariant import (
-    vllm_is_batch_invariant,
-)
 from vllm.platforms import current_platform
 
 try:
@@ -112,7 +110,7 @@ def __init__(
             return
         self.force_multimem = force_multimem
         self.disabled = False
-        if vllm_is_batch_invariant():
+        if envs.VLLM_BATCH_INVARIANT:
             self.disabled = True
 
     def should_use_symm_mem(self, inp: torch.Tensor):

vllm/envs.py

@@ -74,6 +74,7 @@
     VLLM_TARGET_DEVICE: str = "cuda"
     VLLM_MAIN_CUDA_VERSION: str = "12.9"
     VLLM_FLOAT32_MATMUL_PRECISION: Literal["highest", "high", "medium"] = "highest"
+    VLLM_BATCH_INVARIANT: bool = False
     MAX_JOBS: str | None = None
     NVCC_THREADS: str | None = None
     VLLM_USE_PRECOMPILED: bool = False
@@ -280,9 +281,6 @@ def disable_compile_cache() -> bool:
 
 
 def use_aot_compile() -> bool:
-    from vllm.model_executor.layers.batch_invariant import (
-        vllm_is_batch_invariant,
-    )
     from vllm.utils.torch_utils import is_torch_equal_or_newer
 
     default_value = (
@@ -292,7 +290,7 @@ def use_aot_compile() -> bool:
     )
 
     return (
-        not vllm_is_batch_invariant()
+        not bool(int(os.getenv("VLLM_BATCH_INVARIANT", "0")))
         and os.environ.get("VLLM_USE_AOT_COMPILE", default_value) == "1"
     )
 
@@ -498,6 +496,9 @@ def _get_or_set_default() -> str:
         ["highest", "high", "medium"],
         case_sensitive=False,
     ),
+    # Enable batch-invariant mode: deterministic results regardless of
+    # batch composition. Requires NVIDIA GPU with compute capability >= 9.0.
+    "VLLM_BATCH_INVARIANT": lambda: bool(int(os.getenv("VLLM_BATCH_INVARIANT", "0"))),
     # Maximum number of compilation jobs to run in parallel.
     # By default this is the number of CPUs
     "MAX_JOBS": lambda: os.getenv("MAX_JOBS", None),

vllm/lora/ops/triton_ops/utils.py

@@ -11,12 +11,11 @@
 
 from vllm import envs
 from vllm.logger import init_logger
-from vllm.model_executor.layers.batch_invariant import vllm_is_batch_invariant
 from vllm.platforms import current_platform
 from vllm.utils.math_utils import next_power_of_2
 
 logger = init_logger(__name__)
-is_batch_invariant = vllm_is_batch_invariant()
+is_batch_invariant = envs.VLLM_BATCH_INVARIANT
 
 _LORA_A_PTR_DICT: dict[tuple[int, ...], tuple[torch.tensor, ...]] = {}
 _LORA_B_PTR_DICT: dict[tuple[int, ...], tuple[torch.tensor, ...]] = {}

vllm/model_executor/kernels/linear/scaled_mm/marlin.py

@@ -6,7 +6,6 @@
 import torch
 
 import vllm.envs as envs
-from vllm.model_executor.layers.batch_invariant import vllm_is_batch_invariant
 from vllm.model_executor.layers.quantization.utils.fp8_utils import (
     process_fp8_weight_block_strategy,
 )
@@ -42,7 +41,7 @@ def is_supported(
         # Check if platform supports FP8 Marlin
         if not is_fp8_marlin_supported():
             return False, "FP8 Marlin requires compute capability 7.5 or higher"
-        if vllm_is_batch_invariant():
+        if envs.VLLM_BATCH_INVARIANT:
             return False, "FP8 Marlin not supported for batch invariant execution."
         if (
             compute_capability is not None

vllm/model_executor/layers/attention/attention.py

@@ -15,7 +15,6 @@
     maybe_transfer_kv_layer,
 )
 from vllm.model_executor.layers.attention_layer_base import AttentionLayerBase
-from vllm.model_executor.layers.batch_invariant import vllm_is_batch_invariant
 from vllm.model_executor.layers.linear import (
     UnquantizedLinearMethod,
 )
@@ -296,7 +295,7 @@ def __init__(
         if (
             cache_config is not None
             and cache_config.enable_prefix_caching
-            and vllm_is_batch_invariant()
+            and envs.VLLM_BATCH_INVARIANT
             and (
                 self.attn_backend.get_name() == "FLASHINFER"
                 or self.attn_backend.get_name() == "TRITON_MLA"

vllm/model_executor/layers/attention/mla_attention.py

@@ -227,7 +227,6 @@
     maybe_transfer_kv_layer,
 )
 from vllm.model_executor.layers.attention_layer_base import AttentionLayerBase
-from vllm.model_executor.layers.batch_invariant import vllm_is_batch_invariant
 from vllm.model_executor.layers.linear import (
     ColumnParallelLinear,
 )
@@ -372,7 +371,7 @@ def __init__(
         if (
             cache_config is not None
             and cache_config.enable_prefix_caching
-            and vllm_is_batch_invariant()
+            and envs.VLLM_BATCH_INVARIANT
             and (
                 self.attn_backend.get_name() == "TRITON_MLA"
                 or self.attn_backend.get_name() == "FLASHINFER"
@@ -2188,7 +2187,7 @@ def _flash_attn_varlen_diff_headdims(
             # ROCm leverages the upstream flash_attn, which takes a parameter
             # called "return_attn_probs" instead of return_softmax_lse
             kwargs["return_attn_probs"] = return_softmax_lse
-        if vllm_is_batch_invariant():
+        if envs.VLLM_BATCH_INVARIANT:
             kwargs["num_splits"] = 1
 
         attn_out = self.flash_attn_varlen_func(

vllm/model_executor/layers/batch_invariant.py

@@ -6,6 +6,7 @@
 
 import torch
 
+import vllm.envs as envs
 from vllm.logger import init_logger
 from vllm.platforms import current_platform
 from vllm.triton_utils import tl, triton
@@ -986,21 +987,6 @@ def enable_batch_invariant_mode():
     torch.backends.cuda.preferred_blas_library(backend="cublaslt")
 
 
-def _read_vllm_batch_invariant() -> bool:
-    val = os.getenv("VLLM_BATCH_INVARIANT", "0")
-    try:
-        return int(val) != 0
-    except ValueError:
-        return False
-
-
-VLLM_BATCH_INVARIANT: bool = _read_vllm_batch_invariant()
-
-
-def vllm_is_batch_invariant() -> bool:
-    return VLLM_BATCH_INVARIANT
-
-
 def override_envs_for_invariance(
     attention_backend: AttentionBackendEnum | None,
 ):
@@ -1059,7 +1045,7 @@ def init_batch_invariance(
     attention_backend: AttentionBackendEnum | None,
 ):
     # this will hit all the csrc overrides as well
-    if vllm_is_batch_invariant():
+    if envs.VLLM_BATCH_INVARIANT:
         override_envs_for_invariance(attention_backend)
         enable_batch_invariant_mode()
 

vllm/model_executor/layers/fused_moe/fused_moe.py

@@ -14,9 +14,6 @@
 import vllm.model_executor.layers.fused_moe.modular_kernel as mk
 from vllm import _custom_ops as ops
 from vllm.logger import init_logger
-from vllm.model_executor.layers.batch_invariant import (
-    vllm_is_batch_invariant,
-)
 from vllm.model_executor.layers.fused_moe.activation import (
     MoEActivation,
     apply_moe_activation,
@@ -1051,7 +1048,7 @@ def get_moe_configs(
     """
 
     # Avoid optimizing for the batch invariant case. Use default config
-    if vllm_is_batch_invariant():
+    if envs.VLLM_BATCH_INVARIANT:
         return None
 
     # First look up if an optimized configuration is available in the configs
@@ -1232,7 +1229,7 @@ def get_default_config(
     dtype: str | None,
     block_shape: list[int] | None = None,
 ) -> dict[str, int]:
-    if vllm_is_batch_invariant():
+    if envs.VLLM_BATCH_INVARIANT:
         return {
             "BLOCK_SIZE_M": 64,
             "BLOCK_SIZE_N": 64,

vllm/model_executor/layers/fused_moe/router/fused_topk_bias_router.py

@@ -6,11 +6,9 @@
 import torch
 
 import vllm._custom_ops as ops
+import vllm.envs as envs
 from vllm._aiter_ops import rocm_aiter_ops
 from vllm.distributed.eplb.eplb_state import EplbLayerState
-from vllm.model_executor.layers.batch_invariant import (
-    vllm_is_batch_invariant,
-)
 from vllm.model_executor.layers.fused_moe.config import (
     RoutingMethodType,
     get_routing_method_type,
@@ -160,7 +158,7 @@ def fused_topk_bias(
     ) + e_score_correction_bias.unsqueeze(0)
 
     # For batch invariance, use sorted=True to ensure deterministic expert selection
-    use_sorted = vllm_is_batch_invariant()
+    use_sorted = envs.VLLM_BATCH_INVARIANT
     topk_indices = torch.topk(scores_for_choice, k=topk, dim=-1, sorted=use_sorted)[1]
     topk_weights = scores.gather(1, topk_indices)
     if renormalize: