[Hardware] [Intel] Enable Multiprocessing and tensor parallel in CPU backend and update documentation (#6125)

csrc/cpu/torch_bindings.cpp

@@ -4,6 +4,8 @@
 
 #include <torch/library.h>
 
+void init_cpu_threads_env(const std::string& cpu_ids);
+
 TORCH_LIBRARY_EXPAND(TORCH_EXTENSION_NAME, ops) {
   // vLLM custom ops
 
@@ -107,4 +109,9 @@ TORCH_LIBRARY_EXPAND(CONCAT(TORCH_EXTENSION_NAME, _cache_ops), cache_ops) {
   cache_ops.impl("reshape_and_cache", torch::kCPU, &reshape_and_cache);
 }
 
+TORCH_LIBRARY_EXPAND(CONCAT(TORCH_EXTENSION_NAME, _utils), utils) {
+  // CPU utils
+  utils.def("init_cpu_threads_env(str cpu_ids) -> ()", &init_cpu_threads_env);
+}
+
 REGISTER_EXTENSION(TORCH_EXTENSION_NAME)