stage context

Former-commit-id: d42727c2e7183e1d114d0225399e547de7e37a12

oneflow/core/job/scope.proto

@@ -2,15 +2,17 @@ syntax = "proto2";
 package oneflow;
 
 import "oneflow/core/job/mirrored_parallel.proto";
+import "oneflow/core/job/stage_context.proto";
 
 message ScopeProto {
-  required int64 symbol_id = 10;
+  required int64 symbol_id = 1;
+  optional int64 parent_scope_symbol_id = 2;
+  required int64 session_id = 3;
   required int64 job_desc_symbol_id = 20;
   required int64 device_parallel_desc_symbol_id = 30;
   required int64 host_parallel_desc_symbol_id = 40; 
   optional bool enable_cpu_alternative_op = 41 [default = true];
   required OptMirroredParallel opt_mirrored_parallel_conf = 50;
   repeated string scope_op_name_prefixes = 60;
-  optional int64 parent_scope_symbol_id = 70;
-  required int64 session_id = 80;
+  optional StageContext stage_context = 70;
 }

oneflow/core/job/stage_context.proto

+syntax = "proto2";
+package oneflow;
+
+// There are deep learning models that could be divided into sequantial consecutive stages.
+// Each stage is a set of ops
+message StageContext {
+  required int64 num_stages = 1;
+  required int64 stage_id = 2;
+}