feat: integrate bmm_fp8 kernel into sgl-kernel (#3056)

sgl-kernel/src/sgl-kernel/ops/utils.py

@@ -0,0 +1,19 @@
+from typing import Dict, Tuple
+
+import torch
+
+
+def _get_cuda_stream(device: torch.device) -> int:
+    return torch.cuda.current_stream(device).cuda_stream
+
+
+_cache_buf: Dict[Tuple[str, torch.device], torch.Tensor] = {}
+
+
+def _get_cache_buf(name: str, bytes: int, device: torch.device) -> torch.Tensor:
+    key = (name, device)
+    buf = _cache_buf.get(key)
+    if buf is None:
+        buf = torch.empty(bytes, dtype=torch.uint8, device=device)
+        _cache_buf[key] = buf
+    return buf