CUDA Arch Independent (#8813)

sgl-kernel/python/sgl_kernel/__init__.py

 import ctypes
 import os
 import platform
+import shutil
+from pathlib import Path
 
 import torch
 
-SYSTEM_ARCH = platform.machine()
 
-cuda_path = f"/usr/local/cuda/targets/{SYSTEM_ARCH}-linux/lib/libcudart.so.12"
-if os.path.exists(cuda_path):
-    ctypes.CDLL(cuda_path, mode=ctypes.RTLD_GLOBAL)
+# copy & modify from torch/utils/cpp_extension.py
+def _find_cuda_home():
+    """Find the CUDA install path."""
+    # Guess #1
+    cuda_home = os.environ.get("CUDA_HOME") or os.environ.get("CUDA_PATH")
+    if cuda_home is None:
+        # Guess #2
+        nvcc_path = shutil.which("nvcc")
+        if nvcc_path is not None:
+            cuda_home = os.path.dirname(os.path.dirname(nvcc_path))
+        else:
+            # Guess #3
+            cuda_home = "/usr/local/cuda"
+    return cuda_home
+
+
+if torch.version.hip is None:
+    cuda_home = Path(_find_cuda_home())
+
+    if (cuda_home / "lib").is_dir():
+        cuda_path = cuda_home / "lib"
+    elif (cuda_home / "lib64").is_dir():
+        cuda_path = cuda_home / "lib64"
+    else:
+        # Search for 'libcudart.so.12' in subdirectories
+        for path in cuda_home.rglob("libcudart.so.12"):
+            cuda_path = path.parent
+            break
+        else:
+            raise RuntimeError("Could not find CUDA lib directory.")
+
+    cuda_include = (cuda_path / "libcudart.so.12").resolve()
+    if cuda_include.exists():
+        ctypes.CDLL(str(cuda_include), mode=ctypes.RTLD_GLOBAL)
 
 from sgl_kernel import common_ops
 from sgl_kernel.allreduce import *