[ROCm] [CI] Migrate CI to mi300x for v0.27.x (#5886)

Signed-off-by: tjtanaa <tunjian.tan@embeddedllm.com>
Signed-off-by: TJian <tunjian.tan@embeddedllm.com>
Co-authored-by: Hongsheng Liu <liuhongsheng4@huawei.com>

tests/diffusion/attention/test_flash_attn.py

@@ -265,10 +265,15 @@ def test_fa_vs_sdpa():
     print(f"Max absolute difference (valid region): {max_diff:.6f}")
     print(f"Mean absolute difference (valid region): {mean_diff:.6f}")
 
-    # Assert that outputs are close
-    # Using higher tolerance for bfloat16 and different implementations
-    assert max_diff < 0.01, f"Max difference {max_diff} exceeds threshold 0.01"
-    assert mean_diff < 0.001, f"Mean difference {mean_diff} exceeds threshold 0.001"
+    # AITER's ROCm BF16 kernel is deterministic, but differs from ROCm SDPA by
+    # about 1.3% relative error. An absolute-only bound misclassifies that
+    # expected rounding difference for larger output values (for example,
+    # -2.65625 vs -2.6875). Keep the tighter historical bounds elsewhere.
+    if current_omni_platform.is_rocm():
+        torch.testing.assert_close(output_fa_valid, output_sdpa_valid, rtol=1e-2, atol=1.5e-2)
+    else:
+        assert max_diff < 0.01, f"Max difference {max_diff} exceeds threshold 0.01"
+        assert mean_diff < 0.001, f"Mean difference {mean_diff} exceeds threshold 0.001"
 
     print("✓ Case 2 PASSED: FA and SDPA outputs are very close!")