feat(imperative): channel default model format to fbs v2

GitOrigin-RevId: 6066516c313553568c706f4b0bf584d747c9dea8

imperative/python/megengine/core/tensor/megbrain_graph.py

@@ -430,6 +430,7 @@ def dump_graph(
 
     dump_format_map = {
         None: None,
+        "FBS_V2": SerializationFormat.FBS_V2,
         "FBS": SerializationFormat.FBS,
     }
     dump_format = dump_format_map[dump_format]

imperative/python/megengine/jit/tracing.py

@@ -613,8 +613,9 @@ class trace:
             resize_input: whether resize input image to fit input var shape.
             input_transform: a python expression to transform the input data.
                 Example: data / np.std(data)
-            dump_format: using different dump formats. the open source MegEngine defaults to the FBS 
-                format. internal MegEngine have a choice of FBS and internal proprietary formats
+            dump_format: using different dump formats. the open source MegEngine
+            defaults to the FBS_V2 format, there are two format FBS_V2 and FBS to choose,
+            internal MegEngine have an other choice of internal proprietary formats
 
         Keyword Arguments:
 

imperative/python/src/graph_rt.cpp

@@ -308,6 +308,7 @@ void init_graph_rt(py::module m) {
 
     py::enum_<_SerializationFormat>(m, "SerializationFormat")
             .value("FBS", _SerializationFormat::FLATBUFFERS)
+            .value("FBS_V2", _SerializationFormat::FLATBUFFERS_V2)
             .export_values();
 
     m.def("optimize_for_inference",
@@ -384,11 +385,9 @@ void init_graph_rt(py::module m) {
              std::optional<_SerializationFormat> dump_format, py::list& stat,
              py::list& inputs, py::list& outputs, py::list& params) {
               std::vector<uint8_t> buf;
-              ser::GraphDumpFormat format;
+              ser::GraphDumpFormat format = ser::GraphDumpFormat::FLATBUFFERS_V2;
               if (dump_format.has_value()) {
                   format = dump_format.value();
-              } else {
-                  format = {};
               }
               auto dumper = ser::GraphDumper::make(
                       ser::OutputFile::make_vector_proxy(&buf), format);

src/serialization/include/megbrain/serialization/sereg.h

@@ -3,7 +3,6 @@
 #include "megbrain/serialization/opr_load_dump.h"
 #include "megbrain/serialization/opr_registry.h"
 #include "megbrain/serialization/opr_shallow_copy.h"
-#include "megbrain/serialization/oss_opr_load_dump.h"
 #include "megbrain/utils/hash_ct.h"
 
 namespace mgb {