src/Pure/Tools/build_process.scala

       state
         .remove_pending(session_name)
         .make_result(session_name, Process_Result.undefined, output_shasum)
     }
     else {
-      progress.echo((if (store_heap) "Building " else "Running ") + session_name + " ...")
-
-      store.init_output(session_name)
-
       val (numa_node, state1) = state.numa_next_node(build_context.numa_nodes)
       val node_info = Host.Node_Info(build_context.hostname, numa_node)
+
+      progress.echo(
+        (if (store_heap) "Building " else "Running ") + session_name +
+          if_proper(node_info.numa_node, " on " + node_info) + " ...")
+
+      store.init_output(session_name)
+
       val job =
         Build_Job.start_session(build_context, progress, log,
           build_deps.background(session_name), input_shasum, node_info)
       state1.add_running(session_name, job)
     }