rename offset to part_length

Former-commit-id: e33f02f82811568987d02f1da6d5095bc96715f5

oneflow/core/comm_network/epoll/epoll_comm_network.cpp

@@ -78,18 +78,18 @@ void EpollCommNet::RequestRead(int64_t dst_machine_id, void* src_token, void* ds
                                void* read_id) const {
   int32_t total_byte_size = static_cast<const SocketMemDesc*>(src_token)->byte_size;
   CHECK_GT(total_byte_size, 0);
-  int32_t offset = (total_byte_size + epoll_conf_.link_num() - 1) / epoll_conf_.link_num();
-  offset = RoundUp(offset, epoll_conf_.msg_segment_kbyte() * 1024);
-  int32_t part_num = (total_byte_size + offset - 1) / offset;
+  int32_t part_length = (total_byte_size + epoll_conf_.link_num() - 1) / epoll_conf_.link_num();
+  part_length = RoundUp(part_length, epoll_conf_.msg_segment_kbyte() * 1024);
+  int32_t part_num = (total_byte_size + part_length - 1) / part_length;
   for (int32_t link_i = 0; link_i < part_num; ++link_i) {
-    int32_t byte_size = (total_byte_size > offset) ? (offset) : (total_byte_size);
+    int32_t byte_size = (total_byte_size > part_length) ? (part_length) : (total_byte_size);
     CHECK_GT(byte_size, 0);
     total_byte_size -= byte_size;
     SocketMsg msg;
     msg.msg_type = SocketMsgType::kRequestRead;
     msg.request_read_msg.src_token = src_token;
     msg.request_read_msg.dst_token = dst_token;
-    msg.request_read_msg.offset = link_i * offset;
+    msg.request_read_msg.offset = link_i * part_length;
     msg.request_read_msg.byte_size = byte_size;
     msg.request_read_msg.read_id = read_id;
     msg.request_read_msg.part_num = part_num;