[CI] Add batch invariant test to ci (#27842)

Signed-off-by: yewentao256 <[email protected]>

Author: yewentao256

.buildkite/test-pipeline.yaml

@@ -346,6 +346,18 @@ steps:
   commands:
     - pytest -v -s v1/attention
 
+- label: Batch Invariance Tests (H100) # 10min
+  timeout_in_minutes: 25
+  gpu: h100
+  source_file_dependencies:
+    - vllm/
+    - tests/v1/determinism/
+  commands:
+    - export VLLM_WORKER_MULTIPROC_METHOD=spawn
+    - pip install pytest-timeout pytest-forked
+    - pytest -v -s v1/determinism/test_batch_invariance.py
+    - pytest -v -s v1/determinism/test_rms_norm_batch_invariant.py
+
 - label: V1 Test attention (B200) # 10min
   timeout_in_minutes: 30
   gpu: b200

tests/v1/determinism/test_batch_invariance.py

@@ -190,6 +190,7 @@ def test_logprobs_bitwise_batch_invariance_bs1_vs_bsN(
         max_num_seqs=32,
         max_model_len=8192,
         dtype="bfloat16",  # not everything is supported
+        gpu_memory_utilization=0.9,
     )
 
     # Use more realistic prompts for better token generation
@@ -444,6 +445,7 @@ def test_logprobs_without_batch_invariance_should_fail(
     monkeypatch.setenv("VLLM_ATTENTION_BACKEND", backend)
 
     # CRITICAL: Disable batch invariance for this test
+    monkeypatch.setenv("VLLM_BATCH_INVARIANT", "0")
     monkeypatch.setattr(batch_invariant, "VLLM_BATCH_INVARIANT", False)
     seed = int(os.getenv("VLLM_TEST_SEED", "12345"))
     random.seed(seed)

tests/v1/determinism/utils.py

@@ -6,6 +6,7 @@
 import pytest
 import torch
 
+from vllm.attention.utils.fa_utils import flash_attn_supports_mla
 from vllm.platforms import current_platform
 
 skip_unsupported = pytest.mark.skipif(
@@ -18,7 +19,7 @@
     "FLASHINFER",
 ]
 
-if current_platform.is_cuda() and current_platform.is_device_capability(90):
+if flash_attn_supports_mla():
     BACKENDS.append("FLASH_ATTN_MLA")
 
 DEFAULT_MODEL = "Qwen/Qwen3-1.7B"