blob: 58899054037a0c89b0e11c6a55dc193c15d4057a [file] [log] [blame]
# Copyright (C) 2020 Arm Limited or its affiliates. All rights reserved.
#
# SPDX-License-Identifier: Apache-2.0
#
# Licensed under the Apache License, Version 2.0 (the License); you may
# not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
# www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an AS IS BASIS, WITHOUT
# WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
# Description:
# Early optimisation of the network graph, using the rewrite_graph module to do the traversal of the graph. These are
# split into two parts optimise_graph_a and optimise_graph_b.
import math
import numpy as np
from . import fp_math
from . import lut
from . import rewrite_graph
from . import scaling
from .data_type import DataType
from .debug_database import DebugDatabase
from .errors import UnsupportedFeatureError
from .ethos_u55_regs.ethos_u55_regs import resampling_mode
from .numeric_util import clamp_sigmoid
from .numeric_util import full_shape
from .numeric_util import round_away_zero
from .operation import create_activation_function
from .operation import create_avgpool_nop
from .operation import NpuBlockType
from .operation import Op
from .operation import Operation
from .softmax import SoftMax
from .tensor import check_quantized_tens_scaling_equal
from .tensor import create_const_tensor
from .tensor import create_reshape_tensor
from .tensor import QuantizationParameters
from .tensor import Tensor
passthrough_nodes = set((Op.Identity,))
memory_only_ops = set((Op.Reshape,))
def remove_passthrough_tensor(tens, arch, nng):
if len(tens.ops) == 1 and tens.ops[0].type in passthrough_nodes:
assert len(tens.ops[0].inputs) == 1
tens = tens.ops[0].inputs[0]
return tens
def rewrite_concat(tens, arch, nng):
if len(tens.ops) == 1 and tens.ops[0].type.is_concat_op():
concat_op = tens.ops[0]
if tens != concat_op.outputs[0]:
return tens # don't attempt to rewrite the min/max outputs of QuantizedConcat
# Not supported so leave it and run on CPU
if not concat_op.run_on_npu:
return tens
inputs, axis = concat_op.get_concat_inputs_axis()
tens.ops = []
offset = 0
for idx, inp in enumerate(inputs):
new_op = Operation(Op.ConcatSliceWrite, concat_op.name + str(idx))
new_op.inputs = [inp]
new_op.outputs = [tens]
new_op.attrs["concat_axis"] = axis
new_op.attrs["concat_start"] = offset
offset += inp.shape[axis]
new_op.attrs["concat_end"] = offset
new_op.run_on_npu = True
tens.ops.append(new_op)
DebugDatabase.add_optimised(concat_op, new_op)
assert tens.shape[axis] == offset
# If axis corresponds to C-dimension, NHCWB16 can only be used in the output if all the concat_start's are a
# multiple of 16. This as, it is only then the address offset for the ofm, for all operations, will be 16 byte
# aligned. For other values of axis the address offsets will be 16 byte aligned, as they are all based on c = 0
# and those addresses are always 16 byte aligned due to the NHCWB16 format.
if axis == -1 or axis == (len(tens.shape) - 1):
for op in tens.ops:
if op.attrs["concat_start"] % 16 != 0:
tens.avoid_NHCWB16 = True
break
return tens
def rewrite_split(tens, arch, nng):
if len(tens.ops) == 1 and tens.ops[0].type.is_split_op():
split_op = tens.ops[0]
# Not supported so leave it and run on CPU
if not split_op.run_on_npu:
return tens
inp, outputs, axis, offset_start, offset_end = split_op.get_split_inputs_axis()
tens.ops = []
new_op = Operation(Op.SplitSliceRead, split_op.name)
new_op.inputs = [inp]
# For Split the offset cannot be extracted from the tensor so it has to
# be calculated from the index of the output tensor
if axis is not None:
# Get the start and end of the split
offset_start = [0] * len(tens.shape)
offset_end = [0] * len(tens.shape)
for out in outputs:
if out == tens:
break
offset_start[axis] += out.shape[axis]
# If start offset is not a multiple of 16 in the C-dimension, NHCWB16 need to be avoided in the input
if (offset_start[-1] % 16) != 0:
inp.avoid_NHCWB16 = True
offset_end[axis] = offset_start[axis] + tens.shape[axis]
new_op.attrs["split_start"] = offset_start
new_op.attrs["split_end"] = offset_end
new_op.run_on_npu = True
new_op.set_output_tensor(tens)
DebugDatabase.add_optimised(split_op, new_op)
return tens
def needed_total_padding(input_size, stride, filter_size):
out_size = (input_size + stride - 1) // stride
needed_input = (out_size - 1) * stride + filter_size
total_padding = max(0, needed_input - input_size)
return total_padding
def calc_padding_and_skirt(padding_type, kernel_size, stride, input_dims):
ypad = needed_total_padding(int(input_dims[1]), int(stride[1]), int(kernel_size[0]))
xpad = needed_total_padding(int(input_dims[2]), int(stride[2]), int(kernel_size[1]))
if padding_type == b"SAME":
left_pad = (xpad + 0) // 2
right_pad = (xpad + 1) // 2
top_pad = (ypad + 0) // 2
bottom_pad = (ypad + 1) // 2
elif padding_type == b"VALID":
left_pad = 0
right_pad = 0
top_pad = 0
bottom_pad = 0
else:
raise UnsupportedFeatureError("Unknown padding {}".format(str(padding_type)))
padding = (top_pad, left_pad, bottom_pad, right_pad)
skirt = (top_pad, left_pad, ypad - top_pad, xpad - left_pad)
return padding, skirt
def calc_upscaled_padding_and_skirt(padding_type, kernel_size, stride, input_dims, upscaling_factor):
kernel_height, kernel_width = kernel_size[0], kernel_size[1]
if padding_type == b"SAME":
ypad = needed_total_padding(int(input_dims[1]) * upscaling_factor, int(stride[1]), int(kernel_height))
xpad = needed_total_padding(int(input_dims[2]) * upscaling_factor, int(stride[2]), int(kernel_width))
right_pad = max(((xpad + 1) // upscaling_factor) - 1, 0)
bottom_pad = max(((ypad + 1) // upscaling_factor) - 1, 0)
left_pad = max(kernel_width - 1 - right_pad, 0)
top_pad = max(kernel_height - 1 - bottom_pad, 0)
elif padding_type == b"VALID":
right_pad = max(kernel_width - 2, 0)
bottom_pad = max(kernel_height - 2, 0)
left_pad = kernel_width - 1
top_pad = kernel_height - 1
else:
assert 0, "Unknown padding"
padding = (top_pad, left_pad, bottom_pad, right_pad)
skirt = padding
return padding, skirt
def fixup_conv2d_backprop(op, arch, nng):
if op.type == Op.Conv2DBackpropInput:
# flip the inputs
op.inputs[0], op.inputs[2] = op.inputs[2], op.inputs[0]
op.type = Op.Conv2DBackpropInputSwitchedBias
# Update strides
op.attrs.update({"stride_w": 1, "stride_h": 1, "strides": (1, 1, 1, 1)})
return op
# Convert the op to an elementwise add
def convert_resizebilinear_1x1_to_add(op):
op.type = Op.Add
op.name = op.name + "_add"
op.attrs["resizebilinear"] = True
# Create an input tensor filled with zeros
shape = op.outputs[0].shape
tens = Tensor(shape, op.inputs[0].dtype, op.inputs[1].name + "_add")
tens.values = np.zeros(shape)
tens.quant_values = np.zeros(shape, np.uint8)
tens.quantization = QuantizationParameters(0.0, 255.0)
tens.quantization.scale_f32 = 1.0
tens.quantization.zero_point = 0
tens.consumer_list = [op]
tens_op = op.inputs[1].ops[0]
tens_op.set_output_tensor(tens)
# Set the add inputs
op.inputs[1] = op.inputs[0]
op.inputs[0] = tens
return op
# Convert ResizeBilinear to a number of 2x2 pool ops
def convert_resizebilinear_to_2x2_pool(op):
count = 0
pre_op = op
outputs = op.outputs
op.attrs.update({"strides": (1, 1, 1, 1), "ksize": (1, 2, 2, 1)})
if op.attrs["align_corners"]:
shape_modifier = 1
op.attrs["padding"] = b"VALID"
else:
shape_modifier = 0
op.attrs["padding"] = b"SAME"
op.inputs[0].resampling_mode = resampling_mode.NEAREST
upscaled_shape = np.array(op.inputs[0].shape[1:3])
out_shape = np.array(op.outputs[0].shape[1:3])
if (upscaled_shape == upscaled_shape * 2 - shape_modifier).all():
return op
while (upscaled_shape < out_shape).all():
if count == 0:
scaled_op = pre_op
else:
scaled_op = op.clone("_{}".format(count))
scaled_op.inputs[0] = pre_op.outputs[0]
upscaled_shape = upscaled_shape * 2 - shape_modifier
if (upscaled_shape == out_shape).all():
scaled_op.outputs = outputs
scaled_op.outputs[0].ops = [scaled_op]
else:
shape = outputs[0].shape.copy()
shape[1:3] = upscaled_shape[0:2]
out_tens = Tensor(shape, DataType.int16, "{}_{}".format(op.outputs[0].name, count))
out_tens.quantization = op.outputs[0].quantization.clone()
out_tens.quantization.quant_min = np.iinfo(np.int16).min
out_tens.quantization.quant_max = np.iinfo(np.int16).max
scaled_op.set_output_tensor(out_tens)
pre_op = scaled_op
count += 1
# Setup the scale value
if scaled_op.inputs[0].dtype.bits == 8 and scaled_op.outputs[0].dtype.bits == 16:
scaled_op.attrs["rescale"] = 128
elif scaled_op.inputs[0].dtype.bits == 16 and scaled_op.outputs[0].dtype.bits == 8:
scaled_op.attrs["rescale"] = 1 / 128
elif "rescale" in scaled_op.attrs:
del scaled_op.attrs["rescale"]
return op
def fixup_resizebilinear(op, arch, nng):
if op.type == Op.ResizeBilinear and op.run_on_npu:
if op.inputs[0].shape == op.outputs[0].shape:
# Bypass nop resizebilinear
op.inputs = op.inputs[:1]
op.type = Op.Identity
elif op.inputs[0].shape[1] == 1 and op.inputs[0].shape[2] == 1:
convert_resizebilinear_1x1_to_add(op)
else:
convert_resizebilinear_to_2x2_pool(op)
return op
def convert_nop_split_to_identity(op, arch, nng):
if op.type == Op.Split and op.attrs.get("num_splits") == 1:
# the list comprehension should return a list with a single tensor
# if it shouldn't, remove_passthrough_tensor will fail appropriately
op.inputs = [i for i in op.inputs if i.shape == op.outputs[0].shape]
op.type = Op.Identity
return op
def fixup_fully_connected_input(op, arch, nng):
if op.type == Op.FullyConnected:
inp = op.inputs[0]
weights = op.inputs[1]
n_in_elems = weights.shape[-2]
elms = inp.elements()
batch_size = elms // n_in_elems
assert batch_size * n_in_elems == elms
desired_shape = [batch_size, n_in_elems]
if inp.shape != desired_shape:
# mismatch, insert a reshape to fix this.
op.set_input_tensor(create_reshape_tensor(inp, desired_shape), 0)
return op
def convert_batched_fc_to_conv(op, arch, nng):
if op.type == Op.FullyConnected:
ifm = op.inputs[0]
ofm = op.outputs[0]
# Check if the FC is 2D and first dimension indicates batching
if len(ifm.shape) == len(ofm.shape) == 2 and ifm.shape[0] > 1:
n = ifm.shape[0]
batching_split = {4: (2, 2), 8: (2, 4), 16: (4, 4)}
h, w = batching_split.get(n, (1, n))
# Convert to convolution
op.name += "_conv"
op.type = Op.Conv2DBias
op.attrs = {
"dilation": (1, 1, 1, 1),
"dilation_h_factor": 1,
"dilation_w_factor": 1,
"padding": b"SAME",
"stride_h": 1,
"stride_w": 1,
"strides": (1, 1, 1, 1),
}
prev_op = ifm.ops[0]
desired_shape = [1, h, w, ifm.shape[-1]]
if len(ifm.consumer_list) == 1 and prev_op is not None and prev_op.type == Op.Reshape:
# There is a preceding Reshape
# Compare input of prev_op and input of op, to see if prev_op can be removed
ifm_prev_op = prev_op.inputs[0]
if ifm_prev_op.shape == ifm.shape and check_quantized_tens_scaling_equal(ifm_prev_op, ifm):
# prev_op can be removed
op.set_input_tensor(ifm_prev_op, 0)
else:
op.inputs[0].set_all_shapes(desired_shape)
prev_op.set_input_tensor(
create_const_tensor(prev_op.inputs[1].name, [1], DataType.int32, desired_shape), 1
)
prev_op.attrs["new_shape"] = desired_shape
else:
# Add reshape op to the input if there is no preceding reshape
ifm.consumer_list.remove(op)
op.set_input_tensor(create_reshape_tensor(ifm, desired_shape), 0)
# Reshape Weights to be 4D. IO becomes HWIO
weight_tensor = op.inputs[1]
weight_tensor.quant_values = np.expand_dims(np.expand_dims(weight_tensor.quant_values, axis=0), axis=0)
weight_tensor.set_all_shapes(list(weight_tensor.quant_values.shape))
desired_shape = [1, h, w, ofm.shape[-1]]
if (
len(ofm.consumer_list) == 1
and ofm.consumer_list[0] is not None
and ofm.consumer_list[0].type == Op.Reshape
):
# There is a subsequent Reshape
# Compare desired shape and output of consumer op, to see if consumer op can be removed
ofm_cons_op = ofm.consumer_list[0].outputs[0]
if desired_shape == ofm_cons_op.shape and check_quantized_tens_scaling_equal(ofm, ofm_cons_op):
op.outputs[0] = ofm_cons_op
op.outputs[0].ops = [op]
else:
op.outputs[0].set_all_shapes(desired_shape)
else:
# Add rehape op to the output
op.set_output_tensor(create_reshape_tensor(ofm, desired_shape, False))
return op
def fixup_pack_input(op, arch, nng):
if op.type == Op.Pack:
# Pack is also referred to as Stack
# Requires the rewrite_concat function to be called on the op afterwards
axis = int(op.attrs["axis"])
desired_shape = op.inputs[0].shape[:axis] + [1] + op.inputs[0].shape[axis:]
# Construct 1 shape tensor to be used by all inserted reshape ops
new_shape_tens = create_const_tensor(op.name + "_reshape_shape", [1], DataType.int32, desired_shape)
for idx, inp in enumerate(op.inputs):
reshape_out = inp.clone("_reshaped")
reshape_out.set_all_shapes(desired_shape)
reshape_op = Operation(Op.Reshape, "{}{}_reshape".format(op.name, idx))
reshape_op.attrs["new_shape"] = desired_shape
reshape_op.inputs = [inp, new_shape_tens]
reshape_op.set_output_tensor(reshape_out)
DebugDatabase.add_optimised(op, reshape_op)
op.inputs[idx] = reshape_out
op.type = Op.PackReshaped
return op
def unfuse_activation_function(op, arch, nng):
if op.type == Op.ConcatTFLite and op.run_on_npu and op.activation is not None:
act_op = Operation(op.activation.op_type, op.name + op.activation.op_type.name)
op.activation = None
out_tens = op.outputs[0]
intermediate_tens = out_tens.clone("_act_intermediate")
act_op.set_output_tensor(out_tens)
act_op.add_input_tensor(intermediate_tens)
op.set_output_tensor(intermediate_tens)
return op
def fixup_stridedslice_output(tens, arch, nng):
op = tens.ops[0]
if op.run_on_npu and op.type == Op.StridedSlice:
reshape_input_shape = tens.shape
new_axis_mask = op.attrs["new_axis_mask"]
shrink_axis_mask = op.attrs["shrink_axis_mask"]
if shrink_axis_mask != 0:
n = 0
axis = 0
while shrink_axis_mask:
prev_mask = shrink_axis_mask
n += 1
shrink_axis_mask &= shrink_axis_mask - 1
axis = int(math.log2(prev_mask - shrink_axis_mask))
reshape_input_shape = reshape_input_shape[:axis] + [1] + reshape_input_shape[axis:]
assert len(tens.shape) == (len(op.inputs[0].shape) - n)
op.attrs["shrink_axis_mask"] = 0
elif new_axis_mask != 0:
n = 0
axis = 0
while new_axis_mask:
prev_mask = new_axis_mask
n += 1
new_axis_mask &= new_axis_mask - 1
axis = int(math.log2(prev_mask - new_axis_mask))
reshape_input_shape = reshape_input_shape[:axis] + reshape_input_shape[(axis + 1) :]
new_axis_mask >>= 1
assert len(tens.shape) == (len(op.inputs[0].shape) + n)
op.attrs["new_axis_mask"] = 0
else:
# Equal Rank StridedSlice, no need to insert reshape
return tens
# Construct 1 shape tensor to be used by all inserted reshape ops
new_shape_tens = create_const_tensor(op.name + "_reshape_shape", [1], DataType.int32, tens.shape)
for idx, out_tens in enumerate(op.outputs):
reshape_in = out_tens.clone("_reshaped")
reshape_in.set_all_shapes(reshape_input_shape)
reshape_in.ops = [op]
reshape_op = Operation(Op.Reshape, "{}{}_reshape".format(op.name, idx))
reshape_op.attrs["new_shape"] = reshape_input_shape
reshape_op.inputs = [reshape_in, new_shape_tens]
reshape_op.set_output_tensor(out_tens)
op.outputs[idx] = reshape_in
return tens
def fixup_unpack_output(tens, arch, nng):
op = tens.ops[0]
if op.run_on_npu and op.type == Op.Unpack:
# Unpack is also referred to as Unstack
# Requires the rewrite_split function to be called on the op afterwards
axis = int(op.attrs["axis"])
op.type = Op.UnpackReshaped
reshape_input_shape = tens.shape[:axis] + [1] + tens.shape[axis:]
# Construct 1 shape tensor to be used by all inserted reshape ops
new_shape_tens = create_const_tensor(op.name + "_reshape_shape", [1], DataType.int32, tens.shape)
for idx, out_tens in enumerate(op.outputs):
reshape_in = out_tens.clone("_reshaped")
reshape_in.set_all_shapes(reshape_input_shape)
reshape_in.ops = [op]
reshape_op = Operation(Op.Reshape, "{}{}_reshape".format(op.name, idx))
reshape_op.attrs["new_shape"] = reshape_input_shape
reshape_op.inputs = [reshape_in, new_shape_tens]
reshape_op.set_output_tensor(out_tens)
DebugDatabase.add_optimised(op, reshape_op)
op.outputs[idx] = reshape_in
return tens
def add_padding_fields(op, arch, nng):
if op.run_on_npu:
if "padding" in op.attrs:
if op.type.is_conv2d_op() or op.type.is_depthwise_conv2d_op():
kernel_size = op.inputs[1].shape[:2]
input_shape = op.inputs[0].shape
elif op.type.is_pool_op() or op.type.npu_block_type == NpuBlockType.ReduceSum:
kernel_size = op.attrs["ksize"][1:3]
input_shape = op.inputs[0].shape
else:
raise UnsupportedFeatureError("Unknown operation that uses padding: {}".format(op.type))
if op.type == Op.Conv2DBackpropInputSwitchedBias:
upscaling_factor = op.outputs[0].shape[1] // input_shape[1]
padding, skirt = calc_upscaled_padding_and_skirt(
op.attrs["padding"], kernel_size, op.attrs["strides"], input_shape, upscaling_factor
)
else:
dilation_h, dilation_w = op.get_dilation_h_w()
dilated_kernel_size = [dilation_h * (kernel_size[0] - 1) + 1, dilation_w * (kernel_size[1] - 1) + 1]
padding, skirt = calc_padding_and_skirt(
op.attrs["padding"], dilated_kernel_size, op.attrs["strides"], input_shape
)
op.attrs["explicit_padding"] = padding
op.attrs["skirt"] = skirt
return op
# Check if the op can be reordered
def get_prepend_op(op):
inp = op.inputs[0]
# The op should be reordered between prev_op and prep_op
prev_op = inp.ops[-1]
prep_op = None
while prev_op.type in memory_only_ops and len(prev_op.outputs) == 1 and len(prev_op.outputs[0].consumers()) == 1:
prep_op = prev_op
inp = prev_op.inputs[0]
prev_op = inp.ops[-1]
if prev_op is not None and len(prev_op.outputs) == 1 and len(prev_op.outputs[0].consumers()) == 1:
return prep_op
return None
def convert_depthwise_to_conv(op, arch, nng):
# Depthwise is equivalent to a single conv2d if the ifm depth is 1 and
# the ofm depth equals the depth multipler.
# If those conditions are true, then we can perform a simple
# switch of the operator type (and weight order)
if op.type == Op.DepthwiseConv2DBias and (op.attrs["depth_multiplier"] != 1):
ifm_tensor = op.inputs[0]
weight_tensor = op.inputs[1]
ofm_tensor = op.outputs[0]
if (ifm_tensor.shape[3] == 1) and (ofm_tensor.shape[3] == op.attrs["depth_multiplier"]):
# Change op type to Conv2d
op.type = Op.Conv2DBias
del op.attrs["channel_multiplier"]
del op.attrs["depth_multiplier"]
weight_tensor.quant_values = np.transpose(weight_tensor.quant_values, (0, 1, 3, 2))
weight_tensor.set_all_shapes(list(weight_tensor.quant_values.shape))
else:
raise UnsupportedFeatureError(
"Unsupported DepthwiseConv2d with depth_multiplier = {}, ifm channels = {}, ofm channels = {}".format(
op.attrs["depth_multiplier"], ifm_tensor.shape[3], ofm_tensor.shape[3]
)
)
DebugDatabase.add_optimised(op, op)
return op
def reorder_depthwise_weights(op, arch, nng):
if op.type.is_depthwise_conv2d_op():
weight_tensor = op.inputs[1]
weight_tensor.quant_values = np.transpose(weight_tensor.quant_values, (0, 1, 3, 2))
weight_tensor.set_all_shapes(list(weight_tensor.quant_values.shape))
weight_tensor.weight_transpose_depthwise = True
return op
def convert_conv_to_fc(op, arch, nng):
# Conv 1x1 can be equivalent to Fully Connected.
# By representing certain convs as fully connected layers, Vela can better determine wether or not to use
# caching/double buffering for the weights.
# (Weights dont need to be reloaded for convs when IFM H and W are 1)
if op.type == Op.Conv2DBias:
_, h, w, _ = op.inputs[0].shape
kh, kw, _, _ = op.inputs[1].shape
if h == 1 and w == 1 and kh == 1 and kw == 1:
# Overwrite this op as a Fully Connected Op
op.name += "_fc"
op.type = Op.FullyConnected
op.attrs = {
"weights_format": 0,
}
# Reshape Weights to be 2D. HWIO becomes just IO (as H and W are 1, they can just be dropped)
weight_tensor = op.inputs[1]
weight_tensor.quant_values = weight_tensor.quant_values.squeeze(axis=(0, 1))
weight_tensor.set_all_shapes(list(weight_tensor.quant_values.shape))
# The output from a fully connected is expected to be 2D so we need to add a reshape layer to convert it
# back to 4D afterwards as the next layer is expecting that shape
orig_ofm_tensor = op.outputs[0]
# Reshape this ops output to be 2D: {(N*H*W), C} (We know N H and W are all 1 so this becomes {1, C})
fc_ofm_tensor = orig_ofm_tensor.clone("_fc")
fc_ofm_tensor.set_all_shapes([1, fc_ofm_tensor.shape[-1]])
fc_ofm_tensor.ops = [op]
# Add a reshape after the new OFM to convert it back to the original 4D shape
reshape_name = op.name + "_reshape"
new_shape_tens = create_const_tensor(reshape_name + "_shape", [1], DataType.int32, orig_ofm_tensor.shape)
reshape_op = Operation(Op.Reshape, reshape_name)
reshape_op.attrs["new_shape"] = orig_ofm_tensor.shape
reshape_op.inputs = [fc_ofm_tensor, new_shape_tens]
reshape_op.set_output_tensor(orig_ofm_tensor)
# Replace this ops OFM to point to the 2D tensor
op.outputs[0] = fc_ofm_tensor
# Record optimisation in debug database
DebugDatabase.add_optimised(op, reshape_op)
DebugDatabase.add_optimised(op, op)
return op
def fixup_relus_with_differing_ifm_ofm_scaling(op, arch, nng):
if op.run_on_npu and op.type.is_relu_op():
ifm = op.inputs[0]
ofm = op.outputs[0]
# Relu with differing IFM and OFM scaling cannot be fused with another primary op
# and requires its own to be inserted
if not check_quantized_tens_scaling_equal(ifm, ofm):
# Override this op with its own primary op (avgpool)
relu_fused_op = create_avgpool_nop(op.name + "_avgpool")
# And fuse the original activation function to it
relu_fused_op.activation = create_activation_function(op.type)
# Tidy up and assign the ifm and ofm to the new op
ifm.consumer_list.remove(op)
# if not 4d, reshape ifm/ofm
if len(ifm.shape) < 4:
ifm_shaped = create_reshape_tensor(ifm, full_shape(4, ifm.shape, 1))
ifm = ifm_shaped
if len(ofm.shape) < 4:
ofm_shaped = create_reshape_tensor(ofm, full_shape(4, ofm.shape, 1), False)
ofm = ofm_shaped
relu_fused_op.add_input_tensor(ifm)
relu_fused_op.set_output_tensor(ofm)
op = relu_fused_op
return op
# Reorder activation op if it's after the memory only operations
def fixup_act_reorder(op, arch, nng):
if op.type.is_relu_op() or op.type in set((Op.Sigmoid, Op.Tanh)):
prep_op = get_prepend_op(op)
if prep_op is not None:
act_op = op.clone("_reordered")
# There is only one input tensor, overwrite it
act_op.set_input_tensor(prep_op.inputs[0], 0)
act_op_out = act_op.inputs[0].clone("_acted")
act_op_out.quantization = op.outputs[0].quantization.clone()
act_op.set_output_tensor(act_op_out)
# Update the consumer list
act_op_out.consumer_list = op.outputs[0].consumer_list.copy()
act_op_out.consumer_list.append(prep_op)
prep_op.inputs[0] = act_op_out
prep_op.outputs[0].quantization = act_op_out.quantization.clone()
# Mark the op so that it will be removed as passthrough later on
op.type = Op.Identity
# Record optimisation in debug database
DebugDatabase.add_optimised(op, act_op)
DebugDatabase.add_optimised(op, op)
return op
def fixup_elementwise_with_scalars(op, arch, nng):
if op.type.is_binary_elementwise_op():
ifm_tensor, ifm2_tensor, _, _ = op.get_ifm_ifm2_weights_ofm()
if ifm2_tensor.shape != [] and ifm_tensor.shape != []:
diff = len(ifm_tensor.shape) - len(ifm2_tensor.shape)
if diff > 0:
ifm2_tensor.shape = full_shape(len(ifm_tensor.shape), ifm2_tensor.shape, 1)
elif diff < 0:
ifm_tensor.shape = full_shape(len(ifm2_tensor.shape), ifm_tensor.shape, 1)
elif ifm_tensor.shape == [] and ifm_tensor.quant_values is None:
# IFM is marked as a scalar, but is a result of an operation; change it to a shape of size 1
ifm_tensor.shape = len(ifm2_tensor.shape) * [1]
ifm_tensor.storage_shape = ifm_tensor.shape
elif ifm2_tensor.shape == [] and ifm2_tensor.quant_values is None:
# IFM2 is marked as a scalar, but is a result of an operation; change it to a shape of size 1
ifm2_tensor.shape = len(ifm_tensor.shape) * [1]
ifm2_tensor.storage_shape = ifm2_tensor.shape
return op
# Set input/output tensor equivalence to the same id for memory operations
def set_tensor_equivalence(op, arch, nng):
if op.type in memory_only_ops:
eid = op.outputs[0].equivalence_id
for inp in op.inputs:
inp.equivalence_id = eid
return op
def convert_softmax(op, arch, nng):
if op.type == Op.Softmax and op.run_on_npu:
softmax = SoftMax(op)
op = softmax.get_graph()
return op
def convert_mul_max_to_abs_or_lrelu(op, arch, nng):
r"""Whenever there is a subgraph with this topology:
Input X For X = -1 or X > 0
| \ / This subgraph can be replaced with either
| Mul an Abs (if X = -1) or a LeakyReLU (if X > 0)
| /
Max
"""
if op.type == Op.Maximum:
# finds the Mul input(s) to the Max
muls = [i for i in op.inputs if i.ops[0].type == Op.Mul]
if len(muls) == 1:
mul = muls[0].ops[0]
elif len(muls) == 2:
# In the case both inputs are Muls, find the one with the same input as the Max
mul = [m for m in muls if len(set(op.inputs + m.ops[0].inputs)) == 1][0].ops[0]
else:
# No Mul inputs
return op
# make sure the Mul doesn't have any other consumers
mul_ofm = mul.outputs[0]
if len(mul_ofm.consumers()) != 1:
return op
# make sure the Mul doesn't have a fused activation function
if mul.activation:
return op
ifm, ofm = op.get_ifm_ofm()
if ifm is None or ofm is None:
return op
if ifm.dtype not in (DataType.uint8, DataType.int8) or ifm.dtype != ofm.dtype:
return op
if not check_quantized_tens_scaling_equal(ifm, ofm) or not check_quantized_tens_scaling_equal(ifm, mul_ofm):
# rewrite to LeakyRelu currently only makes sense if the quantization is identical
return op
# finds the branched input that goes to both the Max and the Mul
shared = set(op.inputs) & set(mul.inputs)
if len(shared) == 1:
shared_in = shared.pop()
# find the constant scalar input to the Mul
const_tens = (set(mul.inputs) - {shared_in}).pop()
# check that it is a scalar
if const_tens.shape != []:
return op
const = const_tens.ops[0]
# check that it is a constant
if const.type != Op.Const:
return op
# Remove the Mul from the shared input's consumers
shared_in.consumer_list.remove(mul)
else:
return op
val = const.outputs[0].values
if val >= 0:
new_op = Op.LeakyRelu
op.attrs["alpha"] = val
# to produce bit exact results, the alpha is not enough;
# save additional scaling info in attr "alpha_scale", to be used as input
# to the LUT construction
alpha_scalar = const_tens.quant_values - const_tens.quantization.zero_point
mul_ifm_scale = np.double(ifm.quantization.scale_f32)
mul_ifm2_scale = np.double(const_tens.quantization.scale_f32)
mul_ofm_scale = np.double(mul_ofm.quantization.scale_f32)
alpha_scale, alpha_shift = scaling.elementwise_mul_scale(mul_ifm_scale, mul_ifm2_scale, mul_ofm_scale)
op.attrs["alpha_scaling"] = (alpha_scalar, alpha_scale, alpha_shift)
elif val == -1:
new_op = Op.Abs
else:
return op
op.type = new_op
op.name = op.name.replace("Maximum", new_op.name)
op.outputs[0].name = op.outputs[0].name.replace("Maximum", new_op.name)
op.inputs = [shared_in]
# Record optimisation in debug database
DebugDatabase.add_optimised(op, op)
return op
def convert_lrelu_to_mul_max(op, arch):
# Converts LeakyRelu to Max(alpha * IFM, identity * IFM)
# (the opposite of convert_mul_max_to_abs_or_lrelu)
ifm, ofm = op.get_ifm_ofm()
if ifm is None or ofm is None:
return op
# Add multiplication with alpha
mul_alpha = Operation(Op.Mul, op.name + "_mul_alpha")
mul_alpha.add_input_tensor(ifm)
# Create const tensor containing alpha as scalar
alpha = op.attrs["alpha"]
quantization = ifm.quantization.clone()
quantization.min = 0
quantization.max = alpha * (quantization.quant_max - quantization.quant_min)
quantization.scale_f32 = alpha
quantization.zero_point = 0
alpha_tens = create_const_tensor(op.name + "_alpha_scalar", [], ifm.dtype, [1], np.int8, quantization=quantization)
mul_alpha.add_input_tensor(alpha_tens)
fm_alpha = ofm.clone(op.name + "_alpha")
mul_alpha.set_output_tensor(fm_alpha)
DebugDatabase.add_optimised(op, mul_alpha)
if check_quantized_tens_scaling_equal(ifm, ofm):
# No identity multiplication is needed
fm_id = ifm
else:
# Add multiplication with identity
mul_identity = Operation(Op.Mul, op.name + "_mul_identity")
mul_identity.add_input_tensor(ifm)
# Create const tensor containing identity as scalar
quantization = ifm.quantization.clone()
quantization.min = 0
quantization.max = quantization.quant_max - quantization.quant_min
quantization.scale_f32 = 1
quantization.zero_point = 0
identity_tens = create_const_tensor(
op.name + "_id_scalar", [], ifm.dtype, [1], np.uint8, quantization=quantization
)
mul_identity.add_input_tensor(identity_tens)
fm_id = ofm.clone(op.name + "_id")
mul_identity.set_output_tensor(fm_id)
DebugDatabase.add_optimised(op, mul_alpha)
# Convert LeakyRelu to Max, add the results of the multiplication(s) as inputs
op.type = Op.Maximum
op.name = op.name.replace("LeakyRelu", "Maximum")
op.inputs = []
ifm.consumer_list.remove(op)
op.add_input_tensor(fm_alpha)
op.add_input_tensor(fm_id)
DebugDatabase.add_optimised(op, op)
return op
def convert_to_lut(op, lut_values, lut_name):
# Rewrite the operation by Add with scalar 0 + LUT activation
ifm = op.inputs[0]
if ifm is None:
return op
assert ifm.dtype.size_in_bytes() == 1
op.type = Op.Add
op.name = op.name + "_lut_" + lut_name
# Mark as no-op to enable potential fusing optimizations
op.attrs["is_nop"] = True
# Create an input tensor containing scalar zero
quantization = QuantizationParameters(0.0, 255.0)
quantization.scale_f32 = ifm.quantization.scale_f32
quantization.zero_point = 0
tens = create_const_tensor(op.inputs[0].name + "_scalar0", [], ifm.dtype, [0], np.uint8, quantization=quantization)
op.add_input_tensor(tens)
# The LUT must be applied without any preceding rescaling (the LUT itself performs the rescale),
# so even if the OFM has a different scale than the IFM, the generated OFM scale instructions
# should be the same as the IFM
op.forced_output_quantization = ifm.quantization
lut_tensor = lut.create_lut_tensor(op.name + "_values", lut_values, DataType.int8)
op.set_activation_lut(lut_tensor)
return op
def convert_to_lut8(op, fn, fn_name):
# Converts op to a no-op + int8/uint8 LUT which is generated with the given function.
# fn is a function(real) -> real
ifm, ofm = op.get_ifm_ofm()
if ifm.dtype not in (DataType.uint8, DataType.int8) or ifm.dtype != ofm.dtype:
return op
# Generate the LUT
ifm_scale = np.double(ifm.quantization.scale_f32)
ofm_scale = np.double(ofm.quantization.scale_f32)
zp_in = ifm.quantization.zero_point
zp_out = ofm.quantization.zero_point
values = []
ix = range(256) if ifm.dtype == DataType.uint8 else range(-128, 128)
quantized_min = min(ix)
quantized_max = max(ix)
for x in ix:
x_real = ifm_scale * (x - zp_in)
y_real = fn(x_real)
lut_result = round_away_zero(zp_out + y_real / ofm_scale)
lut_result = min(quantized_max, max(quantized_min, lut_result))
values.append(lut_result)
return convert_to_lut(op, values, fn_name)
def convert_lrelu_to_lut(op, arch):
ifm, ofm = op.get_ifm_ofm()
# Generate the LUT
alpha = op.attrs["alpha"]
ifm_scale = np.double(ifm.quantization.scale_f32)
ofm_scale = np.double(ofm.quantization.scale_f32)
zp_in = ifm.quantization.zero_point
zp_out = ofm.quantization.zero_point
identity_scale, identity_shift = scaling.elementwise_mul_scale(ifm_scale, 1, ofm_scale)
alpha_scalar = 1
alpha_scale, alpha_shift = scaling.elementwise_mul_scale(ifm_scale, alpha, ofm_scale)
if "alpha_scaling" in op.attrs:
# The LeakyRelu was the result from convert_mul_max_to_abs_or_lrelu
alpha_scalar, alpha_scale, alpha_shift = op.attrs["alpha_scaling"]
values = []
ix = range(256) if ifm.dtype == DataType.uint8 else range(-128, 128)
quantized_min = min(ix)
quantized_max = max(ix)
for x in ix:
if x < zp_in:
lut_result = zp_out + fp_math.multiply_by_quantized_multiplier(
alpha_scalar * (x - zp_in), alpha_scale, alpha_shift
)
else:
lut_result = zp_out + fp_math.multiply_by_quantized_multiplier(x - zp_in, identity_scale, identity_shift)
lut_result = min(quantized_max, max(quantized_min, lut_result))
values.append(lut_result)
return convert_to_lut(op, values, "lrelu")
def convert_lrelu(op, arch, nng):
# Converts LeakyRelu to a LUT based solution if possible, otherwise a mul + max
if op.type != Op.LeakyRelu:
return op
ifm, ofm = op.get_ifm_ofm()
if ifm is None or ofm is None:
return op
if ifm.dtype in (DataType.uint8, DataType.int8) and ifm.dtype == ofm.dtype:
# use LUT for int8/uint8
return convert_lrelu_to_lut(op, arch)
if check_quantized_tens_scaling_equal(ifm, ofm) and ifm.dtype == ofm.dtype == DataType.int16:
# use LeakyRelu unmodified for int16 with equal input/output scaling
return op
return convert_lrelu_to_mul_max(op, arch)
def convert_tanh_sigmoid_to_lut(op, arch, nng):
# Converts int8/uint8 Sigmoid and Tanh to a LUT based solution
if op.type == Op.Sigmoid:
return convert_to_lut8(op, clamp_sigmoid, "sigmoid")
elif op.type == Op.Tanh:
return convert_to_lut8(op, math.tanh, "tanh")
return op
def remove_unwanted_reshapes(op, arch, nng):
# Try to remove reshapes enclosing ElementWise operator with only one non-constant input
if not op.run_on_npu or not op.type.is_elementwise_op():
return op
# Check if the ElementWise operator only have one non-constant input
non_const_tens = [x for x in op.inputs if x.ops[0].type != Op.Const]
if len(non_const_tens) != 1:
return op
ifm = non_const_tens[0]
# Check if operation is enclosed by Reshapes that can be removed
ofm = op.outputs[0]
prev_op = ifm.ops[0]
if (
len(ifm.consumer_list) == 1
and prev_op.type == Op.Reshape
and len(ofm.consumer_list) == 1
and ofm.consumer_list[0].type == Op.Reshape
):
# Operation is enclosed by reshapes, check if they can be removed
prev_op_ifm, prev_op_ofm = prev_op.get_ifm_ofm()
cons_op = ofm.consumer_list[0]
cons_op_ifm = ofm
cons_op_ofm = cons_op.outputs[0]
if len(prev_op_ifm.shape) == len(cons_op_ofm.shape):
# Check if quantization is the same in the input and output for the reshape ops
if check_quantized_tens_scaling_equal(prev_op_ifm, prev_op_ofm) and check_quantized_tens_scaling_equal(
cons_op_ifm, cons_op_ofm
):
op.set_input_tensor(prev_op_ifm, 0)
op.set_output_tensor(cons_op_ofm)
return op
def fuse_activation_function_with_prev(op, arch, nng):
# if op is a no-op: attempts to move the activation function to the preceding op
if not op.attrs.get("is_nop", False) or op.activation is None:
return op
ifm, ofm = op.get_ifm_ofm()
if ifm is None or ofm is None:
return op
# finds the input(s) to the operation
prev_op = ifm.ops[0]
# Note: the below checks on prev_op require that a first optimize pass on the full graph has been performed
fuse = (
prev_op.run_on_npu
and prev_op.type.npu_block_type != NpuBlockType.Default
and len(ifm.ops) == 1
and len(prev_op.outputs[0].consumers()) == 1
and prev_op.activation is None
)
if op.activation_lut is not None and arch.shram_reserved_unused_banks == 0:
# TODO: if SHRAM LUT space is shared with SHRAM ACC (32, 64 MAC),
# LUT currently only works correctly for elementwise ops
fuse = False
if not fuse:
return op
# Move the fused activation function + corresponding info to prev_op
prev_op.activation = op.activation
prev_op.forced_output_quantization = op.forced_output_quantization
if op.activation_lut is not None:
prev_op.set_activation_lut(op.activation_lut)
# Bypass op
prev_op.set_output_tensor(ofm)
DebugDatabase.add_optimised(op, prev_op)
return op
def add_attrs_to_resizebilinear(op, arch, nng):
if op.type == Op.ResizeBilinear and op.run_on_npu:
input_tensor = op.inputs[0]
upscaled_shape = [input_tensor.shape[1] * 2, input_tensor.shape[2] * 2]
out_shape = op.outputs[0].shape[1:3]
if not op.attrs["align_corners"] and out_shape == upscaled_shape:
# this means the output is supposed to be a x2 upscale,
# so we need to do SAME padding
op.attrs["padding"] = b"SAME"
elif op.attrs["align_corners"] and out_shape == [upscaled_shape[0] - 1, upscaled_shape[1] - 1]:
# here we can just run the avg pool without padding and
# produce a (M * 2 - 1, N * 2 - 1) sized output
op.attrs["padding"] = b"VALID"
else:
return op
input_tensor.resampling_mode = resampling_mode.NEAREST
op.attrs.update({"strides": (1, 1, 1, 1), "ksize": (1, 2, 2, 1)})
return op
def fixup_bias_tensors(op, arch, nng):
if op.type.needs_bias() and op.bias is None:
# Op has no bias, add bias tensor filled with zeros
nr_biases = op.inputs[1].shape[-1]
bias_values = [0] * nr_biases
bias_tensor = create_const_tensor(op.name + "_bias", [nr_biases], DataType.int32, bias_values)
bias_tensor.quant_values = bias_tensor.values
op.set_input_tensor(bias_tensor, -1)
return op
def supported_operator_check(op, arch, nng):
op.run_on_npu = arch.supported_operators.is_operator_supported(op)
return op
def _record_optimised(op, arch):
if op.type != Op.Const:
DebugDatabase.add_optimised(op, op)
def optimise_graph_a(nng, arch, verbose_graph=False):
if verbose_graph:
nng.print_graph()
op_rewrite_list = [
set_tensor_equivalence,
supported_operator_check,
# then do any rewrites of supported operators
convert_depthwise_to_conv,
convert_conv_to_fc,
convert_softmax,
fixup_fully_connected_input,
convert_batched_fc_to_conv,
fixup_pack_input,
unfuse_activation_function,
fixup_conv2d_backprop,
fixup_relus_with_differing_ifm_ofm_scaling,
fixup_act_reorder,
fixup_elementwise_with_scalars,
reorder_depthwise_weights,
fixup_resizebilinear,
fixup_bias_tensors,
convert_nop_split_to_identity,
convert_mul_max_to_abs_or_lrelu,
remove_unwanted_reshapes,
convert_lrelu,
convert_tanh_sigmoid_to_lut,
]
for idx, sg in enumerate(nng.subgraphs):
# rewrite graph pass
nng.subgraphs[idx] = rewrite_graph.rewrite_graph_pre_order(
nng, sg, arch, [], op_rewrite_list, rewrite_unsupported=False,
)
for idx, sg in enumerate(nng.subgraphs):
# remove passthrough tensors and attempt further optimizations
nng.subgraphs[idx] = rewrite_graph.rewrite_graph_pre_order(
nng, sg, arch, [remove_passthrough_tensor], [fuse_activation_function_with_prev, add_padding_fields]
)
# Post-optimisation operator debug tracing
for sg in nng.subgraphs:
rewrite_graph.visit_graph_post_order(sg.output_tensors, arch, [], [_record_optimised])
if verbose_graph:
nng.print_graph()
return nng
def optimise_graph_b(nng, arch, verbose_graph=False):
if verbose_graph:
nng.print_graph()
for idx, sg in enumerate(nng.subgraphs):
# combined rewrite graph pass
nng.subgraphs[idx] = rewrite_graph.rewrite_graph_pre_order(
nng, sg, arch, [fixup_unpack_output, fixup_stridedslice_output, rewrite_concat, rewrite_split], []
)
if verbose_graph:
nng.print_graph()
return nng