[AMD] Skip AITER FP8 ASM prefill when GQA is unsupported (#38467)

test/registered/unit/layers/attention/test_aiter_fp8_asm_gqa.py

@@ -0,0 +1,27 @@
+"""Tests for the AITER FP8 FMHA ASM GQA routing guard."""
+
+import unittest
+
+from sglang.srt.layers.attention.aiter_backend import _aiter_fp8_asm_supports_gqa
+from sglang.test.ci.ci_register import register_cpu_ci
+
+register_cpu_ci(est_time=5, suite="base-a-test-cpu")
+
+
+class TestAiterFp8AsmSupportsGqa(unittest.TestCase):
+    def test_supported_asm_gqa_ratios(self):
+        for ratio in (1, 2, 4, 8, 16):
+            with self.subTest(ratio=ratio):
+                self.assertTrue(_aiter_fp8_asm_supports_gqa(ratio * 4, 4))
+
+    def test_rejects_qwen38_27b_gqa6(self):
+        self.assertFalse(_aiter_fp8_asm_supports_gqa(24, 4))
+
+    def test_rejects_other_unsupported_ratios(self):
+        for num_q_heads, num_kv_heads in ((12, 4), (32, 1), (24, 0), (23, 4), (0, 4)):
+            with self.subTest(num_q_heads=num_q_heads, num_kv_heads=num_kv_heads):
+                self.assertFalse(_aiter_fp8_asm_supports_gqa(num_q_heads, num_kv_heads))
+
+
+if __name__ == "__main__":
+    unittest.main()