[CPU] Add native CPU kernel for MurmurHash32 (#35604)

Co-authored-by: Ma Mingfei <mingfei.ma@intel.com>

test/registered/cpu/test_sampling.py

@@ -0,0 +1,56 @@
+import sys
+
+import pytest
+import sgl_kernel  # noqa: F401
+import torch
+
+from sglang.kernels.ops.sampling.murmur_hash import murmur_hash32
+from sglang.test.ci.ci_register import register_cpu_ci
+
+register_cpu_ci(est_time=5, suite="stage-a-test-cpu-intel")
+
+
+@pytest.mark.parametrize("positions_dtype", [torch.int64, torch.uint64])
+def test_murmur_hash32_cpu_known_values(positions_dtype):
+    seed = torch.tensor([0, 1, 42, 0x123456789ABCDEF0], dtype=torch.uint64)
+
+    positions = torch.tensor([0, 7, 123, 456], dtype=positions_dtype)
+
+    col_indices = torch.tensor([0, 1, 2, 17], dtype=torch.int64)
+
+    actual = murmur_hash32(seed, positions, col_indices)
+
+    expected = torch.tensor(
+        [
+            [2167721464, 10027521, 2423355346, 2203067026],
+            [3755322398, 4196701286, 1002451629, 183234019],
+            [772287619, 548237471, 2740678348, 3656549299],
+            [3746406971, 2891010872, 104055988, 3372550890],
+        ],
+        dtype=torch.uint32,
+    )
+
+    torch.testing.assert_close(actual, expected)
+
+
+@pytest.mark.parametrize("positions_dtype", [torch.int64, torch.uint64])
+def test_murmur_hash32_cpu_shape_and_dtype(positions_dtype):
+    seed = torch.tensor([1, 2, 3], dtype=torch.uint64)
+
+    positions = torch.tensor([10, 20, 30], dtype=positions_dtype)
+
+    col_indices = torch.arange(128, dtype=torch.int64)
+
+    actual = murmur_hash32(
+        seed,
+        positions,
+        col_indices,
+    )
+
+    assert actual.device.type == "cpu"
+    assert actual.dtype == torch.uint32
+    assert actual.shape == (3, 128)
+
+
+if __name__ == "__main__":
+    sys.exit(pytest.main([__file__]))