diff --git a/imperative/python/megengine/tools/README.md b/imperative/python/megengine/tools/README.md
new file mode 100644
index 0000000000000000000000000000000000000000..4e38fe4c01a95a61349739f9c179cf556e1dced2
--- /dev/null
+++ b/imperative/python/megengine/tools/README.md
@@ -0,0 +1,8 @@
+# MegEngine Tools
+
+This directory contains executable python files.
+Use these files in the following way (replace `xxx` to specific file name, like `network_visualize`):
+
+```
+python -m megengine.tools.xxx
+```
diff --git a/imperative/python/megengine/tools/__init__.py b/imperative/python/megengine/tools/__init__.py
new file mode 100644
index 0000000000000000000000000000000000000000..e69de29bb2d1d6434b8b29ae775ad8c2e48c5391
diff --git a/imperative/python/megengine/utils/compare_binary_iodump.py b/imperative/python/megengine/tools/compare_binary_iodump.py
similarity index 64%
rename from imperative/python/megengine/utils/compare_binary_iodump.py
rename to imperative/python/megengine/tools/compare_binary_iodump.py
index b6be0ced0d24ed193ef75b57bec3644a5247099d..9a4ef87a561ba695b7dfeb08a8415797ab1f8273 100755
--- a/imperative/python/megengine/utils/compare_binary_iodump.py
+++ b/imperative/python/megengine/tools/compare_binary_iodump.py
@@ -1,3 +1,4 @@
+#! /usr/bin/env python3
 # MegEngine is Licensed under the Apache License, Version 2.0 (the "License")
 #
 # Copyright (c) 2014-2021 Megvii Inc. All rights reserved.
@@ -7,12 +8,55 @@
 # "AS IS" BASIS, WITHOUT ARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 import argparse
 import os
+import struct
 import textwrap
 from pathlib import Path
 
 import numpy as np
 
-from megengine.utils import plugin
+
+def load_tensor_binary(fobj):
+    """
+    Load a tensor dumped by the :class:`BinaryOprIODump` plugin; the actual
+    tensor value dump is implemented by ``mgb::debug::dump_tensor``.
+
+    :param fobj: file object, or a string that contains the file name.
+    :return: tuple ``(tensor_value, tensor_name)``.
+    """
+    if isinstance(fobj, str):
+        with open(fobj, "rb") as fin:
+            return load_tensor_binary(fin)
+
+    DTYPE_LIST = {
+        0: np.float32,
+        1: np.uint8,
+        2: np.int8,
+        3: np.int16,
+        4: np.int32,
+        # 5: _mgb.intb1,
+        # 6: _mgb.intb2,
+        # 7: _mgb.intb4,
+        8: None,
+        9: np.float16,
+        # quantized dtype start from 100000
+        # see MEGDNN_PARAMETERIZED_DTYPE_ENUM_BASE in
+        # dnn/include/megdnn/dtype.h
+        100000: np.uint8,
+        100001: np.int32,
+        100002: np.int8,
+    }
+
+    header_fmt = struct.Struct("III")
+    name_len, dtype, max_ndim = header_fmt.unpack(fobj.read(header_fmt.size))
+    assert (
+        DTYPE_LIST[dtype] is not None
+    ), "Cannot load this tensor: dtype Byte is unsupported."
+
+    shape = list(struct.unpack("I" * max_ndim, fobj.read(max_ndim * 4)))
+    while shape[-1] == 0:
+        shape.pop(-1)
+    name = fobj.read(name_len).decode("ascii")
+    return np.fromfile(fobj, dtype=DTYPE_LIST[dtype]).reshape(shape), name
 
 
 def check(v0, v1, name, max_err):
@@ -26,9 +70,9 @@ def check(v0, v1, name, max_err):
     )
     vdiv = np.max([np.abs(v0), np.abs(v1), np.ones_like(v0)], axis=0)
     err = np.abs(v0 - v1) / vdiv
-    check = err > max_err
-    if check.sum():
-        idx = tuple(i[0] for i in np.nonzero(check))
+    rst = err > max_err
+    if rst.sum():
+        idx = tuple(i[0] for i in np.nonzero(rst))
         raise AssertionError(
             "{} not equal: "
             "shape={} nonequal_idx={} v0={} v1={} err={}".format(
@@ -79,8 +123,8 @@ def main():
     files1 = sorted(files1)
 
     for i, j in zip(files0, files1):
-        val0, name0 = plugin.load_tensor_binary(i)
-        val1, name1 = plugin.load_tensor_binary(j)
+        val0, name0 = load_tensor_binary(i)
+        val1, name1 = load_tensor_binary(j)
         name = "{}: \n{}\n{}\n".format(
             i, "\n  ".join(textwrap.wrap(name0)), "\n  ".join(textwrap.wrap(name1))
         )
diff --git a/imperative/python/megengine/tools/network_visualize.py b/imperative/python/megengine/tools/network_visualize.py
new file mode 100755
index 0000000000000000000000000000000000000000..181a302727e46c3d7a4d4d71369cd69c93eea5eb
--- /dev/null
+++ b/imperative/python/megengine/tools/network_visualize.py
@@ -0,0 +1,176 @@
+#! /usr/bin/env python3
+# MegEngine is Licensed under the Apache License, Version 2.0 (the "License")
+#
+# Copyright (c) 2014-2021 Megvii Inc. All rights reserved.
+#
+# Unless required by applicable law or agreed to in writing,
+# software distributed under the License is distributed on an
+# "AS IS" BASIS, WITHOUT ARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+import argparse
+
+import numpy as np
+
+from megengine.core.tensor.dtype import is_quantize
+from megengine.logger import get_logger
+from megengine.utils.module_stats import (
+    print_flops_stats,
+    print_params_stats,
+    sizeof_fmt,
+)
+from megengine.utils.network import Network
+
+logger = get_logger(__name__)
+
+
+def visualize(
+    model_path: str,
+    log_path: str,
+    bar_length_max: int = 20,
+    log_params: bool = True,
+    log_flops: bool = True,
+):
+    r"""
+    Load megengine dumped model and visualize graph structure with tensorboard log files.
+    Can also record and print model's statistics like :func:`~.net_stats`
+
+    :param model_path: dir path for megengine dumped model.
+    :param log_path: dir path for tensorboard graph log.
+    :param bar_length_max: size of bar indicating max flops or parameter size in net stats.
+    :param log_params: whether print and record params size.
+    :param log_flops: whether print and record op flops.
+    """
+    try:
+        from tensorboard.compat.proto.attr_value_pb2 import AttrValue
+        from tensorboard.compat.proto.config_pb2 import RunMetadata
+        from tensorboard.compat.proto.graph_pb2 import GraphDef
+        from tensorboard.compat.proto.node_def_pb2 import NodeDef
+        from tensorboard.compat.proto.step_stats_pb2 import (
+            AllocatorMemoryUsed,
+            DeviceStepStats,
+            NodeExecStats,
+            StepStats,
+        )
+        from tensorboard.compat.proto.tensor_shape_pb2 import TensorShapeProto
+        from tensorboard.compat.proto.versions_pb2 import VersionDef
+        from tensorboardX import SummaryWriter
+    except ImportError:
+        logger.error(
+            "TensorBoard and TensorboardX are required for visualize.", exc_info=True
+        )
+        return
+
+    graph = Network.load(model_path)
+    writer = SummaryWriter(log_path)
+
+    def process_name(name):
+        return name.replace(".", "/").encode(encoding="utf-8")
+
+    node_list = []
+    flops_list = []
+    params_list = []
+    for node in graph.all_oprs:
+        if hasattr(node, "output_idx"):
+            node_oup = node.outputs[node.output_idx]
+        else:
+            if len(node.outputs) != 1:
+                logger.warning(
+                    "OpNode {} has more than one output and not has 'output_idx' attr.".format(
+                        node
+                    )
+                )
+            node_oup = node.outputs[0]
+
+        inp_list = [process_name(var.owner.name) for var in node.inputs]
+        attr = {
+            "_output_shapes": AttrValue(
+                list=AttrValue.ListValue(
+                    shape=[
+                        TensorShapeProto(
+                            dim=[TensorShapeProto.Dim(size=d) for d in node_oup.shape]
+                        )
+                    ]
+                )
+            ),
+        }
+        if hasattr(node, "calc_flops"):
+            flops_num = node.calc_flops()
+            # add op flops attr
+            attr["flops"] = AttrValue(s=sizeof_fmt(flops_num).encode(encoding="utf-8"))
+            flops_list.append(
+                dict(
+                    name=node.name,
+                    class_name=node.type,
+                    input_shapes=[i.shape for i in node.inputs],
+                    output_shapes=[o.shape for o in node.outputs],
+                    flops_num=flops_num,
+                    flops_cum=0,
+                )
+            )
+        if node.type == "ImmutableTensor":
+            param_dim = np.prod(node_oup.shape)
+            # TODO: consider other quantize dtypes
+            param_bytes = 1 if is_quantize(node_oup.dtype) else 4
+            # add tensor size attr
+            attr["size"] = AttrValue(
+                s=sizeof_fmt(param_dim * param_bytes).encode(encoding="utf-8")
+            )
+            params_list.append(
+                dict(
+                    name=node.name,
+                    shape=node_oup.shape,
+                    param_dim=param_dim,
+                    bits=param_bytes * 8,
+                    size=param_dim * param_bytes,
+                    size_cum=0,
+                    mean="{:.2g}".format(node.numpy().mean()),
+                    std="{:.2g}".format(node.numpy().std()),
+                )
+            )
+        node_list.append(
+            NodeDef(
+                name=process_name(node.name), op=node.type, input=inp_list, attr=attr,
+            )
+        )
+
+    total_flops, total_params = 0, 0
+    if log_params:
+        total_params = print_params_stats(params_list, bar_length_max)
+    if log_flops:
+        total_flops = print_flops_stats(flops_list, bar_length_max)
+
+    graph_def = GraphDef(node=node_list, versions=VersionDef(producer=22))
+
+    device = "/device:CPU:0"
+    stepstats = RunMetadata(
+        step_stats=StepStats(dev_stats=[DeviceStepStats(device=device)])
+    )
+    writer._get_file_writer().add_graph((graph_def, stepstats))
+    return total_params, total_flops
+
+
+def main():
+    parser = argparse.ArgumentParser(
+        description="load a megengine dumped model and export log file for tensorboard visualization.",
+        formatter_class=argparse.ArgumentDefaultsHelpFormatter,
+    )
+    parser.add_argument("model_path", help="dumped model path.")
+    parser.add_argument("log_path", help="tensorboard log path.")
+    parser.add_argument(
+        "--bar_length_max",
+        type=int,
+        default=20,
+        help="size of bar indicating max flops or parameter size in net stats.",
+    )
+    parser.add_argument(
+        "--log_params",
+        action="store_true",
+        help="whether print and record params size.",
+    )
+    parser.add_argument(
+        "--log_flops", action="store_true", help="whether print and record op flops.",
+    )
+    visualize(**vars(parser.parse_args()))
+
+
+if __name__ == "__main__":
+    main()
diff --git a/imperative/python/megengine/utils/profile_analyze.py b/imperative/python/megengine/tools/profile_analyze.py
similarity index 99%
rename from imperative/python/megengine/utils/profile_analyze.py
rename to imperative/python/megengine/tools/profile_analyze.py
index 6722670bf01d9fdae6bf4993874ad77e0f11fa9e..071e06606f44e5c6b58b070774e67a696231ed12 100755
--- a/imperative/python/megengine/utils/profile_analyze.py
+++ b/imperative/python/megengine/tools/profile_analyze.py
@@ -1,4 +1,4 @@
-# -*- coding: utf-8 -*-
+#! /usr/bin/env python3
 # MegEngine is Licensed under the Apache License, Version 2.0 (the "License")
 #
 # Copyright (c) 2014-2021 Megvii Inc. All rights reserved.
diff --git a/imperative/python/megengine/utils/net_stats.py b/imperative/python/megengine/utils/module_stats.py
similarity index 58%
rename from imperative/python/megengine/utils/net_stats.py
rename to imperative/python/megengine/utils/module_stats.py
index 68eced78ec6f7145c099f3f3c78bfba3ea9e53a8..46753cbe92bd8a32d824a21509533e663e6fe203 100644
--- a/imperative/python/megengine/utils/net_stats.py
+++ b/imperative/python/megengine/utils/module_stats.py
@@ -84,26 +84,125 @@ hook_modules = (
 )
 
 
-def net_stats(model, input_size, bar_length_max=20, log_params=True, log_flops=True):
-    def dict2table(list_of_dict, header):
-        table_data = [header]
-        for d in list_of_dict:
-            row = []
-            for h in header:
-                v = ""
-                if h in d:
-                    v = d[h]
-                row.append(v)
-            table_data.append(row)
-        return table_data
-
-    def sizeof_fmt(num, suffix="B"):
-        for unit in ["", "Ki", "Mi", "Gi", "Ti", "Pi", "Ei", "Zi"]:
-            if abs(num) < 1024.0:
-                return "{:3.3f} {}{}".format(num, unit, suffix)
-            num /= 1024.0
-        sign_str = "-" if num < 0 else ""
-        return "{}{:.1f} {}{}".format(sign_str, num, "Yi", suffix)
+def dict2table(list_of_dict, header):
+    table_data = [header]
+    for d in list_of_dict:
+        row = []
+        for h in header:
+            v = ""
+            if h in d:
+                v = d[h]
+            row.append(v)
+        table_data.append(row)
+    return table_data
+
+
+def sizeof_fmt(num, suffix="B"):
+    for unit in ["", "Ki", "Mi", "Gi", "Ti", "Pi", "Ei", "Zi"]:
+        if abs(num) < 1024.0:
+            return "{:3.3f} {}{}".format(num, unit, suffix)
+        num /= 1024.0
+    sign_str = "-" if num < 0 else ""
+    return "{}{:.1f} {}{}".format(sign_str, num, "Yi", suffix)
+
+
+def print_flops_stats(flops, bar_length_max=20):
+    flops_list = [i["flops_num"] for i in flops]
+    max_flops_num = max(flops_list + [0])
+    # calc total flops and set flops_cum
+    total_flops_num = 0
+    for d in flops:
+        total_flops_num += int(d["flops_num"])
+        d["flops_cum"] = sizeof_fmt(total_flops_num, suffix="OPs")
+
+    for i in flops:
+        f = i["flops_num"]
+        i["flops"] = sizeof_fmt(f, suffix="OPs")
+        r = i["ratio"] = f / total_flops_num
+        i["percentage"] = "{:.2f}%".format(r * 100)
+        bar_length = int(f / max_flops_num * bar_length_max)
+        i["bar"] = "#" * bar_length
+
+    header = [
+        "name",
+        "class_name",
+        "input_shapes",
+        "output_shapes",
+        "flops",
+        "flops_cum",
+        "percentage",
+        "bar",
+    ]
+
+    total_flops_str = sizeof_fmt(total_flops_num, suffix="OPs")
+    total_var_size = sum(sum(s[1] for s in i["output_shapes"]) for i in flops)
+    flops.append(
+        dict(name="total", flops=total_flops_str, output_shapes=total_var_size)
+    )
+
+    logger.info("flops stats: \n" + tabulate.tabulate(dict2table(flops, header=header)))
+
+    return total_flops_num
+
+
+def print_params_stats(params, bar_length_max=20):
+    total_param_dims, total_param_size = 0, 0
+    for d in params:
+        total_param_dims += int(d["param_dim"])
+        total_param_size += int(d["size"])
+        d["size"] = sizeof_fmt(d["size"])
+        d["size_cum"] = sizeof_fmt(total_param_size)
+
+    for d in params:
+        ratio = d["param_dim"] / total_param_dims
+        d["ratio"] = ratio
+        d["percentage"] = "{:.2f}%".format(ratio * 100)
+
+    # construct bar
+    max_ratio = max([d["ratio"] for d in params])
+    for d in params:
+        bar_length = int(d["ratio"] / max_ratio * bar_length_max)
+        d["size_bar"] = "#" * bar_length
+
+    param_size = sizeof_fmt(total_param_size)
+    params.append(dict(name="total", param_dim=total_param_dims, size=param_size,))
+
+    header = [
+        "name",
+        "shape",
+        "mean",
+        "std",
+        "param_dim",
+        "bits",
+        "size",
+        "size_cum",
+        "percentage",
+        "size_bar",
+    ]
+
+    logger.info(
+        "param stats: \n" + tabulate.tabulate(dict2table(params, header=header))
+    )
+
+    return total_param_size
+
+
+def net_stats(
+    model: m.Module,
+    input_size: int,
+    bar_length_max: int = 20,
+    log_params: bool = True,
+    log_flops: bool = True,
+):
+    r"""
+    Calculate and print ``model``'s statistics by adding hook and record Module's inputs outputs size.
+
+    :param model: model that need to get stats info.
+    :param input_size: size of input for running model and calculating stats.
+    :param bar_length_max: size of bar indicating max flops or parameter size in net stats.
+    :param log_params: whether print and record params size.
+    :param log_flops: whether print and record op flops.
+    """
 
     def get_byteswidth(tensor):
         if dtype.is_quantize(tensor.dtype):
@@ -113,87 +212,6 @@ def net_stats(model, input_size, bar_length_max=20, log_params=True, log_flops=T
         else:
             return 4
 
-    def print_flops_stats(flops):
-        flops_list = [i["flops_num"] for i in flops]
-        max_flops_num = max(flops_list + [0])
-        # calc total flops and set flops_cum
-        total_flops_num = 0
-        for d in flops:
-            total_flops_num += int(d["flops_num"])
-            d["flops_cum"] = sizeof_fmt(total_flops_num, suffix="OPs")
-
-        for i in flops:
-            f = i["flops_num"]
-            i["flops"] = sizeof_fmt(f, suffix="OPs")
-            r = i["ratio"] = f / total_flops_num
-            i["percentage"] = "{:.2f}%".format(r * 100)
-            bar_length = int(f / max_flops_num * bar_length_max)
-            i["bar"] = "#" * bar_length
-
-        header = [
-            "name",
-            "class_name",
-            "input_shapes",
-            "output_shapes",
-            "flops",
-            "flops_cum",
-            "percentage",
-            "bar",
-        ]
-
-        total_flops_str = sizeof_fmt(total_flops_num, suffix="OPs")
-        total_var_size = sum(sum(s[1] for s in i["output_shapes"]) for i in flops)
-        flops.append(
-            dict(name="total", flops=total_flops_str, output_shapes=total_var_size)
-        )
-
-        logger.info(
-            "flops stats: \n" + tabulate.tabulate(dict2table(flops, header=header))
-        )
-
-        return total_flops_num
-
-    def print_params_stats(params):
-        total_param_dims, total_param_size = 0, 0
-        for d in params:
-            total_param_dims += int(d["param_dim"])
-            total_param_size += int(d["size"])
-            d["size"] = sizeof_fmt(d["size"])
-            d["size_cum"] = sizeof_fmt(total_param_size)
-
-        for d in params:
-            ratio = d["param_dim"] / total_param_dims
-            d["ratio"] = ratio
-            d["percentage"] = "{:.2f}%".format(ratio * 100)
-
-        # construct bar
-        max_ratio = max([d["ratio"] for d in params])
-        for d in params:
-            bar_length = int(d["ratio"] / max_ratio * bar_length_max)
-            d["size_bar"] = "#" * bar_length
-
-        param_size = sizeof_fmt(total_param_size)
-        params.append(dict(name="total", param_dim=total_param_dims, size=param_size,))
-
-        header = [
-            "name",
-            "shape",
-            "mean",
-            "std",
-            "param_dim",
-            "bits",
-            "size",
-            "size_cum",
-            "percentage",
-            "size_bar",
-        ]
-
-        logger.info(
-            "param stats: \n" + tabulate.tabulate(dict2table(params, header=header))
-        )
-
-        return total_param_size
-
     def net_stats_hook(module, input, output, name=""):
         class_name = str(module.__class__).split(".")[-1].split("'")[0]
 
@@ -273,8 +291,8 @@ def net_stats(model, input_size, bar_length_max=20, log_params=True, log_flops=T
 
     total_flops, total_params = 0, 0
     if log_params:
-        total_params = print_params_stats(params)
+        total_params = print_params_stats(params, bar_length_max)
     if log_flops:
-        total_flops = print_flops_stats(flops)
+        total_flops = print_flops_stats(flops, bar_length_max)
 
     return total_params, total_flops
diff --git a/imperative/python/megengine/utils/network.py b/imperative/python/megengine/utils/network.py
index f26e8086becfb933a025c3661e3b06b03a6166e1..8bcf4d8927766e97e42c0fc59ec41c822291a3b8 100644
--- a/imperative/python/megengine/utils/network.py
+++ b/imperative/python/megengine/utils/network.py
@@ -19,9 +19,9 @@ from ..core._imperative_rt import ComputingGraph
 from ..core.tensor import megbrain_graph as G
 from .comp_graph_tools import get_dep_vars, get_opr_type, get_oprs_seq
 from .network_node import (
-    NetworkNode,
     Host2DeviceCopy,
     ImmutableTensor,
+    NetworkNode,
     OpNode,
     VarNode,
     str_to_mge_class,
@@ -606,9 +606,7 @@ class NodeFilterType(NodeFilter):
     _node_type = None
 
     def __init__(self, node_iter, node_type):
-        assert issubclass(node_type, NetworkNode), "bad opr type: {}".format(
-            node_type
-        )
+        assert issubclass(node_type, NetworkNode), "bad opr type: {}".format(node_type)
         super().__init__(node_iter)
         self._node_type = node_type
 
diff --git a/imperative/python/megengine/utils/network_node.py b/imperative/python/megengine/utils/network_node.py
index ada2df466fad1e23f45f4df628e7f888a86e4ff1..58a5982eaff895663bec85a56080b7d010e5af7e 100644
--- a/imperative/python/megengine/utils/network_node.py
+++ b/imperative/python/megengine/utils/network_node.py
@@ -10,6 +10,8 @@ import json
 import sys
 from typing import Callable
 
+import numpy as np
+
 from ..core import _imperative_rt as rt
 from ..core._wrap import Device
 from ..core.ops import builtin
@@ -52,7 +54,7 @@ class VarNode(NetworkNode):
         return self.var.dtype if self.var else None
 
     def set_owner_opr(self, owner_opr):
-        self.owner_opr = owner_opr
+        self.owner = owner_opr
 
 
 class OpNode(NetworkNode):
@@ -223,6 +225,9 @@ class Elemwise(OpNode):
     type = "Elemwise"
     opdef = builtin.Elemwise
 
+    def calc_flops(self):
+        return np.prod(self.outputs[0].shape)
+
 
 class Reduce(OpNode):
     type = "Reduce"
@@ -250,11 +255,21 @@ class MatrixMul(OpNode):
     type = "MatrixMul"
     opdef = builtin.MatrixMul
 
+    def calc_flops(self):
+        assert len(self.inputs[0].shape) == 2 and len(self.outputs[0].shape) == 2
+        mid_shape = self.inputs[0].shape[1]
+        return np.prod(self.outputs[0].shape) * mid_shape
+
 
 class BatchedMatrixMul(OpNode):
     type = "BatchedMatmul"
     opdef = builtin.BatchedMatrixMul
 
+    def calc_flops(self):
+        assert len(self.inputs[0].shape) == 3 and len(self.outputs[0].shape) == 3
+        mid_shape = self.inputs[0].shape[2]
+        return np.prod(self.outputs[0].shape) * mid_shape
+
 
 class Dot(OpNode):
     type = "Dot"
@@ -270,6 +285,18 @@ class ConvolutionForward(OpNode):
     type = "Convolution"
     opdef = builtin.Convolution
 
+    def calc_flops(self):
+        param_W_shape = self.inputs[1].shape
+        kh = param_W_shape[-2]
+        kw = param_W_shape[-1]
+        if len(param_W_shape) == 5:
+            num_input = param_W_shape[2]
+        else:
+            num_input = param_W_shape[1]
+        NCHW = np.prod(self.outputs[0].shape)
+        # N x Cout x H x W x  (Cin x Kw x Kh)
+        return NCHW * (num_input * kw * kh)
+
 
 class ConvolutionBackwardData(OpNode):
     type = "ConvTranspose"
@@ -316,6 +343,18 @@ class ConvBiasForward(OpNode):
         obj.params["dtype"] = opr.outputs[0].dtype
         return obj
 
+    def calc_flops(self):
+        param_W_shape = self.inputs[1].shape
+        kh = param_W_shape[-2]
+        kw = param_W_shape[-1]
+        if len(param_W_shape) == 5:
+            num_input = param_W_shape[2]
+        else:
+            num_input = param_W_shape[1]
+        NCHW = np.prod(self.outputs[0].shape)
+        # N x Cout x H x W x  (Cin x Kw x Kh + bias)
+        return NCHW * (num_input * kw * kh + 1)
+
 
 class BatchConvBiasForward(OpNode):
     type = "BatchConvBias"
@@ -331,6 +370,7 @@ class BatchConvBiasForward(OpNode):
 class BatchNormForward(OpNode):
     type = "BatchNorm"
     opdef = builtin.BatchNorm
+    output_idx = -1
 
 
 class ROIAlignForward(OpNode):
@@ -622,6 +662,9 @@ class ElemwiseMultiType(OpNode):
         obj.params["dtype"] = opr.outputs[0].dtype
         return obj
 
+    def calc_flops(self):
+        return np.prod(self.outputs[0].shape)
+
 
 class CvtColorForward(OpNode):
     type = "CvtColor"
diff --git a/imperative/python/megengine/utils/plugin.py b/imperative/python/megengine/utils/plugin.py
deleted file mode 100644
index a50634c23146e4b71517575eaa182ad6622ff88d..0000000000000000000000000000000000000000
--- a/imperative/python/megengine/utils/plugin.py
+++ /dev/null
@@ -1,57 +0,0 @@
-# -*- coding: utf-8 -*-
-# MegEngine is Licensed under the Apache License, Version 2.0 (the "License")
-#
-# Copyright (c) 2014-2021 Megvii Inc. All rights reserved.
-#
-# Unless required by applicable law or agreed to in writing,
-# software distributed under the License is distributed on an
-# "AS IS" BASIS, WITHOUT ARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-import struct
-
-import numpy as np
-
-
-def load_tensor_binary(fobj):
-    """
-    Load a tensor dumped by the :class:`BinaryOprIODump` plugin; the actual
-    tensor value dump is implemented by ``mgb::debug::dump_tensor``.
-
-    Multiple values can be compared by ``tools/compare_binary_iodump.py``.
-
-    :param fobj: file object, or a string that contains the file name.
-    :return: tuple ``(tensor_value, tensor_name)``.
-    """
-    if isinstance(fobj, str):
-        with open(fobj, "rb") as fin:
-            return load_tensor_binary(fin)
-
-    DTYPE_LIST = {
-        0: np.float32,
-        1: np.uint8,
-        2: np.int8,
-        3: np.int16,
-        4: np.int32,
-        # 5: _mgb.intb1,
-        # 6: _mgb.intb2,
-        # 7: _mgb.intb4,
-        8: None,
-        9: np.float16,
-        # quantized dtype start from 100000
-        # see MEGDNN_PARAMETERIZED_DTYPE_ENUM_BASE in
-        # dnn/include/megdnn/dtype.h
-        100000: np.uint8,
-        100001: np.int32,
-        100002: np.int8,
-    }
-
-    header_fmt = struct.Struct("III")
-    name_len, dtype, max_ndim = header_fmt.unpack(fobj.read(header_fmt.size))
-    assert (
-        DTYPE_LIST[dtype] is not None
-    ), "Cannot load this tensor: dtype Byte is unsupported."
-
-    shape = list(struct.unpack("I" * max_ndim, fobj.read(max_ndim * 4)))
-    while shape[-1] == 0:
-        shape.pop(-1)
-    name = fobj.read(name_len).decode("ascii")
-    return np.fromfile(fobj, dtype=DTYPE_LIST[dtype]).reshape(shape), name