diff options
author | Louis Verhaard <louis.verhaard@arm.com> | 2020-11-26 11:42:04 +0100 |
---|---|---|
committer | patrik.gustavsson <patrik.gustavsson@arm.com> | 2020-12-07 14:51:52 +0000 |
commit | 1e17018d1aabff6b2a4cc5e8e3758678347b84c5 (patch) | |
tree | 8c06cb5a9f68e45fce96d9f17aac9a86f28ad912 /ethosu/vela/register_command_stream_util.py | |
parent | 32c7f5bbbccae480a0bb0c0e5b74a37dd9412023 (diff) | |
download | ethos-u-vela-1e17018d1aabff6b2a4cc5e8e3758678347b84c5.tar.gz |
MLBEDSW-3643: Refactor blockdep calculation
Moved blockdep calculation and other helper functions for
code generation to a separate file.
Change-Id: I2f8ccea478654272ebf42217fc5c1800e9ad177a
Signed-off-by: Louis Verhaard <louis.verhaard@arm.com>
Diffstat (limited to 'ethosu/vela/register_command_stream_util.py')
-rw-r--r-- | ethosu/vela/register_command_stream_util.py | 543 |
1 files changed, 543 insertions, 0 deletions
diff --git a/ethosu/vela/register_command_stream_util.py b/ethosu/vela/register_command_stream_util.py new file mode 100644 index 00000000..ca7e6bc6 --- /dev/null +++ b/ethosu/vela/register_command_stream_util.py @@ -0,0 +1,543 @@ +# 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: +# Utility functions for code generation +from typing import List +from typing import NamedTuple +from typing import Optional + +from . import numeric_util +from .api import NpuActivationOp +from .api import NpuAddressRange +from .api import NpuBlockOperation +from .api import NpuDmaOperation +from .api import NpuElementWiseOp +from .api import NpuFeatureMap +from .api import NpuKernel +from .api import NpuLayout +from .api import NpuOperation +from .api import NpuOperationType +from .api import NpuPadding +from .api import NpuShape3D +from .architecture_features import ArchitectureFeatures +from .architecture_features import Block +from .architecture_features import Rect +from .operation import Kernel +from .operation import PointXYZ +from ethosu.vela.range_set import AccessDirection +from ethosu.vela.range_set import MemoryAccessSet +from ethosu.vela.range_set import MemoryRangeSet + +# base address slot for memory to memory transfer +BASE_PTR_INDEX_MEM2MEM = int((1 << 8) | (3 << 0)) + + +UNARY_ELEMWISE_OPS = set((NpuElementWiseOp.ABS, NpuElementWiseOp.LRELU, NpuElementWiseOp.CLZ,)) + + +def to_npu_kernel(kernel: Kernel) -> NpuKernel: + """Converts the given internally used kernel object to NpuKernel (of public API)""" + return NpuKernel( + kernel.width, kernel.height, kernel.stride.x, kernel.stride.y, kernel.dilation.x, kernel.dilation.y + ) + + +def to_kernel(kernel: Optional[NpuKernel]) -> Kernel: + """Converts the given public API object to Kernel (used internally)""" + if kernel is None: + return Kernel(1, 1) + return Kernel(kernel.width, kernel.height, kernel.stride_x, kernel.stride_y, kernel.dilation_x, kernel.dilation_y) + + +def has_ifm2(npu_op: NpuBlockOperation) -> bool: + """Checks if op has non-scalar IFM2""" + return npu_op.ifm2 is not None and npu_op.ifm2_scalar is None + + +def is_dma_op(npu_op: NpuOperation) -> bool: + """Checks if op is a DMA operation""" + return npu_op.op_type == NpuOperationType.Dma + + +def shape3d_size(shape: NpuShape3D) -> int: + return shape.width * shape.height * shape.depth + + +def shape3d_to_rect(shape: NpuShape3D) -> Rect: + return Rect(0, 0, 0, shape.width - 1, shape.height - 1, shape.depth - 1) + + +# ------------------------------------------------------------------- +# ADDRESSING/STRIDES (helper functions) +# ------------------------------------------------------------------- + + +def ranges_overlap(range1: NpuAddressRange, range2: NpuAddressRange) -> bool: + """Checks if the ranges overlap""" + return range1.region == range2.region and numeric_util.overlaps( + range1.address, range1.address + range1.length, range2.address, range2.address + range2.length + ) + + +def range_lists_overlap(list1: List[Optional[NpuAddressRange]], list2: List[Optional[NpuAddressRange]]) -> bool: + """Checks if there is any address overlap between list1 and list2""" + for range1 in list1: + if range1 is None: + continue + for range2 in list2: + if range2 is not None and ranges_overlap(range1, range2): + return True + return False + + +def get_strides(fm: NpuFeatureMap) -> NpuShape3D: + """Calculates STRIDE_C/Y/X""" + if fm.strides is not None: + return fm.strides + elem_size = fm.data_type.size_in_bytes() + if fm.layout == NpuLayout.NHWC: + stride_c = elem_size + stride_x = fm.shape.depth * stride_c + stride_y = fm.shape.width * stride_x + else: + stride_x = 16 * elem_size + stride_c = stride_x * fm.shape.width + stride_y = elem_size * fm.shape.width * numeric_util.round_up(fm.shape.depth, 16) + return NpuShape3D(depth=stride_c, height=stride_y, width=stride_x) + + +def get_address(fm: NpuFeatureMap, strides: NpuShape3D, y: int, x: int, c: int) -> int: + """Returns address of given coordinate""" + t = 0 + BRICK = 16 + stride_c = BRICK * fm.data_type.size_in_bytes() if fm.layout == NpuLayout.NHWC else strides.depth + stride_x = BRICK * fm.data_type.size_in_bytes() if fm.layout == NpuLayout.NHCWB16 else strides.width + if x >= fm.tiles.width_0: + x -= fm.tiles.width_0 + t = 1 + if y >= fm.tiles.height_1: + y -= fm.tiles.height_1 + t += 2 + elif y >= fm.tiles.height_0: + y -= fm.tiles.height_0 + t += 2 + elem_size = fm.data_type.size_in_bytes() + return ( + fm.tiles.addresses[t] + y * strides.height + x * stride_x + (c // BRICK) * stride_c + int(c % BRICK) * elem_size + ) + + +def get_address_range( + fm: NpuFeatureMap, strides: NpuShape3D, y0: int, x0: int, c0: int, y1: int, x1: int, c1: int +) -> NpuAddressRange: + """ + Gets address range for (y0, x0, c0) - (y1, x1, c1) (inclusive, so the second coordinate is within the fm). + The begin and end coordinates must be within the same tile. + """ + addr0 = get_address(fm, strides, y0, x0, c0) + addr1 = get_address(fm, strides, y1, x1, c1) + return NpuAddressRange(region=fm.region, address=addr0, length=addr1 - addr0 + fm.data_type.size_in_bytes()) + + +def get_h_ranges( + fm: NpuFeatureMap, strides: NpuShape3D, y0: int, x0: int, c0: int, y1: int, x1: int, c1: int +) -> List[NpuAddressRange]: + """ + Gets address ranges for (y0, x0, c0) - (y1, x1, c1) (inclusive, so the second coordinate is within the fm); + the begin and end coordinates must be within the same tile. + Divides the area in horizontal "stripes" of height 1, and returns the address ranges for these "stripes". + """ + return [get_address_range(fm, strides, y, x0, c0, y, x1, c1) for y in range(y0, y1 + 1)] + + +def get_address_ranges_for_area(fm: NpuFeatureMap, start: PointXYZ, end: PointXYZ) -> List[NpuAddressRange]: + """ + Returns a list of adddress ranges that covers the area start - end (inclusive). + Divides the area in horizontal "stripes" of height 1, and returns the address ranges for these "stripes". + + For example, for the area marked with X (in a feature map with 4 tiles) as input, this function would return + 6 address ranges: the address ranges for 1-height areas [AAA, BBB, CC, DD, EEE, FF] + + .....|.... .....|.... + t0 ..XXX|XX.. t1 t0 ..AAA|CC.. t1 + ..XXX|XX.. ..BBB|DD.. + -----+---- --> -----+---- + t2 ..XXX|XX.. t3 t2 ..EEE|FF.. t3 + .....|.... .....|.... + """ + strides = get_strides(fm) + height_0, height_1, width_0 = fm.tiles.height_0, fm.tiles.height_1, fm.tiles.width_0 + h, w, c = fm.shape + y0, x0, c0 = start.y, start.x, start.z + y1, x1, c1 = min(end.y, h - 1), min(end.x, w - 1), min(end.z, c - 1) + ranges = [] + if x0 < width_0 and y0 < height_0: + # Horizontal ranges for tile 0 + ranges.extend(get_h_ranges(fm, strides, y0, x0, c0, min(y1, height_0 - 1), min(x1, width_0 - 1), c1)) + if x1 >= width_0 and y0 < height_1: + # Horizontal ranges for tile 1 + ranges.extend(get_h_ranges(fm, strides, y0, max(x0, width_0), c0, min(y1, height_1 - 1), x1, c1)) + if x0 < width_0 and y1 >= height_0: + # Horizontal ranges for tile 2 + ranges.extend(get_h_ranges(fm, strides, max(y0, height_0), x0, c0, y1, min(x1, width_0 - 1), c1)) + if x1 >= width_0 and y1 >= height_1: + # Horizontal ranges for tile 3 + ranges.extend(get_h_ranges(fm, strides, max(y0, height_1), max(x0, width_0), c0, y1, x1, c1)) + return ranges + + +def get_address_ranges(fm: NpuFeatureMap) -> List[Optional[NpuAddressRange]]: + """Returns 4 adddress ranges, one for every tile, None if the tile is not in use""" + strides = get_strides(fm) + height, width, depth = fm.shape.height, fm.shape.width, fm.shape.depth + height_0, height_1, width_0 = fm.tiles.height_0, fm.tiles.height_1, fm.tiles.width_0 + t0 = get_address_range(fm, strides, 0, 0, 0, min(height, height_0) - 1, min(width, width_0) - 1, depth - 1,) + if width > width_0: + t1 = get_address_range(fm, strides, 0, width_0, 0, min(height, height_1) - 1, width - 1, depth - 1) + else: + t1 = None + if height > height_0: + t2 = get_address_range(fm, strides, height_0, 0, 0, height - 1, min(width, width_0) - 1, depth - 1) + else: + t2 = None + if t1 is not None and t2 is not None: + t3 = get_address_range(fm, strides, height_1, width_0, 0, height - 1, width - 1, depth - 1) + else: + t3 = None + return [t0, t1, t2, t3] + + +# ------------------------------------------------------------------- +# DMA_WAIT/KERNEL_WAIT +# ------------------------------------------------------------------- + + +class Watermark(NamedTuple): + npu: int + dma: int + + +def memory_range_set(range: NpuAddressRange) -> MemoryRangeSet: + return MemoryRangeSet(range.region, range.address, range.address + range.length) + + +def get_dma_memory_accesses(dma_op: NpuDmaOperation) -> MemoryAccessSet: + """Returns the address that are read and written by the given DMA operation""" + res = MemoryAccessSet() + res.add(memory_range_set(dma_op.src), AccessDirection.Read) + res.add(memory_range_set(dma_op.dest), AccessDirection.Write) + return res + + +def get_op_memory_accesses(npu_op: NpuBlockOperation, arch: ArchitectureFeatures) -> MemoryAccessSet: + """Returns the addresses that are read and written by the given operation""" + assert npu_op.ifm is not None and npu_op.ofm is not None + # Read addresses + read_ranges = get_address_ranges(npu_op.ifm) + if has_ifm2(npu_op): + assert npu_op.ifm2 is not None + read_ranges.extend(get_address_ranges(npu_op.ifm2)) + read_ranges.extend(npu_op.weights) + read_ranges.extend(npu_op.biases) + if npu_op.activation is not None and npu_op.activation.op_type == NpuActivationOp.TABLE_LOOKUP: + address = arch.available_shram_banks(True) * arch.shram_bank_size + read_ranges.append(NpuAddressRange(region=BASE_PTR_INDEX_MEM2MEM, address=address, length=2048)) + # Written addresses + write_ranges = get_address_ranges(npu_op.ofm) + # Add write access to SHRAM, needed when LUTs can overwrite accumulator banks + uses_lut = npu_op.activation is not None and npu_op.activation.op_type == NpuActivationOp.TABLE_LOOKUP + written_shram_size = arch.available_shram_banks(uses_lut) * arch.shram_bank_size + write_ranges.append(NpuAddressRange(region=BASE_PTR_INDEX_MEM2MEM, address=0, length=written_shram_size)) + + res = MemoryAccessSet() + for read_range in read_ranges: + if read_range is not None: + res.add(memory_range_set(read_range), AccessDirection.Read) + for write_range in write_ranges: + if write_range is not None: + res.add(memory_range_set(write_range), AccessDirection.Write) + return res + + +def get_wait_dependency( + arch: ArchitectureFeatures, npu_op_list: List[NpuOperation], memory_accesses, op_index: int, watermark: Watermark +): + """Used to calculate whether DMA wait or kernel wait operations are needed""" + npu_op = npu_op_list[op_index] + op_access = memory_accesses[npu_op] + index = op_index - 1 + + # NPU dependency tracking + npu_outstanding = -1 + npu_ops = 0 + npu_index = watermark.npu + + # DMA dependency tracking + dma_outstanding = -1 + dma_ops = 0 + dma_index = watermark.dma + + # Seek back in the command stream looking for NPU or DMA dependencies + # but only as far as the first dependency or the watermarks (dependencies + # before this point have been satisfied already). + # The watermark moves to after the latest element we must wait for, not + # the command that issues the wait. + # NPU->NPU dependency is handled via blockdep. + while (index >= npu_index) or (index >= dma_index): + prev_op = npu_op_list[index] + prev_access = memory_accesses[prev_op] + + # Check NPU consuming DMA output + if is_dma_op(prev_op): + if index >= dma_index: + if not is_dma_op(npu_op): + if (dma_outstanding == -1) and prev_access.conflicts(op_access): + dma_outstanding = dma_ops + dma_ops += 1 # Count DMA ops in the pipeline + if dma_ops >= arch.max_outstanding_dma: + dma_index = max(index + 1, dma_index) + # Check DMA consuming NPU output + else: + if index >= npu_index: + if is_dma_op(npu_op) and npu_outstanding == -1 and prev_access.conflicts(op_access): + npu_outstanding = npu_ops + npu_ops += 1 # Count NPU ops in the pipeline + if npu_ops >= arch.max_outstanding_kernels: + npu_index = max(index + 1, npu_index) + + index -= 1 + + # Update DMA watermark if we didn't see any and the NPU pipeline is full + if (dma_ops == 0) and (npu_ops >= arch.max_outstanding_kernels): + dma_index = op_index + + # Bring the search watermark forwards as we complete for those dependencies + watermark = Watermark(npu_index, dma_index) + outstanding = Watermark(npu_outstanding, dma_outstanding) + + return watermark, outstanding + + +# ------------------------------------------------------------------- +# BLOCKDEP +# ------------------------------------------------------------------- + + +def get_ifm_ofm_block_depth(arch: ArchitectureFeatures, npu_op: NpuBlockOperation) -> int: + # Note: NOT equivalent to the normal ifm block depth calculation since + # it takes into account 'depthless' block operations by returning full + # depth + if npu_op.op_type == NpuOperationType.Conv2D: + res = arch.calc_ifm_block_depth(npu_op.ifm.shape.depth, npu_op.ifm.data_type.size_in_bits()) + return res + return npu_op.ofm.shape.depth + + +def coords_intersect(start_a: PointXYZ, end_a: PointXYZ, start_b: PointXYZ, end_b: PointXYZ) -> bool: + """Checks if the two areas overlap""" + start_x = max(start_a.x, start_b.x) + end_x = min(end_a.x, end_b.x) + start_y = max(start_a.y, start_b.y) + end_y = min(end_a.y, end_b.y) + start_z = max(start_a.z, start_b.z) + end_z = min(end_a.z, end_b.z) + return ((end_x - start_x) > 0) and ((end_y - start_y) > 0) and ((end_z - start_z) > 0) + + +def intersects( + ifm: NpuFeatureMap, + ifm_start_coord: PointXYZ, + ifm_end_coord: PointXYZ, + prev_ofm: NpuFeatureMap, + ofm_start_coord: PointXYZ, + ofm_end_coord: PointXYZ, +) -> bool: + """Checks if the given IFM area overlaps with the given OFM area""" + if ifm.shape == prev_ofm.shape and ifm.tiles == prev_ofm.tiles: + # Common case: prev_op.ofm == op.ifm; in this case it suffices to check + # if the xyz coordinates overlap, which is quick and easy + res = coords_intersect(ifm_start_coord, ifm_end_coord, ofm_start_coord, ofm_end_coord) + else: + # The OFM produces a part of the IFM (e.g. a stripe), or the IFM consumes part of the OFM. + # In this case, address comparison between the two areas is needed + ifm_ranges = get_address_ranges_for_area(ifm, ifm_start_coord, ifm_end_coord) + prev_ofm_ranges = get_address_ranges_for_area(prev_ofm, ofm_start_coord, ofm_end_coord) + res = range_lists_overlap(ifm_ranges, prev_ofm_ranges) + return res + + +# Block job dependency: +# Does the VOLUME of IFMs for block job B(0) overlap with VOLUME of OFMs block jobs A(8,9,10) +# +# A | B +# ----------------------+------------------ +# .... 3,4,5,6,7,8,9,10 | 0,1,2,3,4,5,6,8 10 < JOB NUMBER +# |<------->| dependency offset +# + + +def get_offset_block_coords(area: Rect, block: Block, offset: int) -> Optional[PointXYZ]: + """ + Get the coordinates of a block offset from either the end (negative) + or the start (zero or positive) of the given 3D area + """ + size = area.size() + # Dimensions of the region, in blocks + width_blocks = numeric_util.round_up_divide(size.width, block.width) + height_blocks = numeric_util.round_up_divide(size.height, block.height) + depth_blocks = numeric_util.round_up_divide(size.depth, block.depth) + total_blocks = width_blocks * height_blocks * depth_blocks + if offset < 0: + index = total_blocks + offset + else: + index = offset + + if index >= total_blocks: + return None + + # Coordinates of the indexed block + coord_z = block.depth * (index % depth_blocks) + coord_y = block.height * (index // (depth_blocks * width_blocks)) + coord_x = block.width * ((index // depth_blocks) % width_blocks) + + return PointXYZ(x=coord_x + area.x, y=coord_y + area.y, z=coord_z + area.z) + + +def get_first_job_input_volume( + arch: ArchitectureFeatures, + ifm: Rect, + ofm: Rect, + ifm_block_depth, + ofm_block: Block, + kernel: Kernel, + padding: NpuPadding, + block_offset: int, +): + # Get ifm block size (jobs are invisibly decomposed into subkernels) + ifm_block = arch.get_ifm_block_size(ifm_block_depth, ofm_block, kernel, arch.ofm_block_max) + ifm_depth_blocks = numeric_util.round_up_divide(ifm.size().depth, ifm_block_depth) + + # Which OFM block are we calculating + ofm_coord = get_offset_block_coords(ofm, ofm_block, block_offset // ifm_depth_blocks) + if ofm_coord is None: + return None + + # Coordinate of the source IFM block + ifm_coord_x = max(0, ofm_coord[0] * kernel.stride.x - padding.left) + ifm_coord_y = max(0, ofm_coord[1] * kernel.stride.y - padding.right) + ifm_coord_z = ifm.z + (block_offset % ifm_depth_blocks) * ifm_block.depth + + # IFM block that will be sampled for the FIRST+block_offset job in the next operator's OFM + start_coord = PointXYZ(x=ifm_coord_x, y=ifm_coord_y, z=ifm_coord_z) + end_coord = PointXYZ( + x=start_coord[0] + ifm_block.width, y=start_coord[1] + ifm_block.height, z=start_coord[2] + ifm_block.depth, + ) + return (start_coord, end_coord, 1) # start, end, total jobs + + +def get_prev_job_output_volume(ofm: Rect, ofm_block: Block, block_offset: int): + assert block_offset >= 0 + + # Get OFM block's volume coordinates + start_coord = get_offset_block_coords(ofm, ofm_block, -1 - block_offset) + if start_coord is None: + return None + end_coord = PointXYZ( + x=start_coord.x + ofm_block.width, y=start_coord.y + ofm_block.height, z=start_coord.z + ofm_block.depth, + ) + return (start_coord, end_coord, 1) # start, end, total jobs for this OFM block + + +def calc_blockdep(arch: ArchitectureFeatures, prev_op: Optional[NpuBlockOperation], npu_op: NpuBlockOperation,) -> int: + """Calculates the value of the BLOCKDEP register""" + if prev_op is None: + return 0 + assert npu_op.ifm is not None + assert prev_op.ofm is not None + # Check if IFM or IFM2 overlaps with prev op's OFM + prev_ofm_ranges = get_address_ranges(prev_op.ofm) + ifm_ranges = get_address_ranges(npu_op.ifm) + ifm_overlaps = range_lists_overlap(prev_ofm_ranges, ifm_ranges) + if has_ifm2(npu_op): + assert npu_op.ifm2 is not None + ifm2_ranges = get_address_ranges(npu_op.ifm2) + ifm2_overlaps = range_lists_overlap(prev_ofm_ranges, ifm2_ranges) + else: + ifm2_overlaps = False + if ifm_overlaps and ifm2_overlaps: + # Both IFM and IFM2 overlap (should be rare) + return 0 + if not ifm_overlaps and not ifm2_overlaps: + # No overlap between prev OFM and IFM/IFM2 + return ArchitectureFeatures.MAX_BLOCKDEP + if ifm2_overlaps and shape3d_size(npu_op.ifm2.shape) < shape3d_size(npu_op.ifm.shape): + # Prev OFM produces IFM2 which is broadcasted (this should be rare) + return 0 + # Prev OFM overlaps with IFM or IFM2; calculate the blockdep + prev_block_config = prev_op.block_config + block_config = npu_op.block_config + overlapping_fm = npu_op.ifm if ifm_overlaps else npu_op.ifm2 + assert overlapping_fm is not None + + cur_ifm_block_depth = get_ifm_ofm_block_depth(arch, npu_op) + cur_ofm_block = Block(block_config.width, block_config.height, block_config.depth) + cur_ofm_rect = shape3d_to_rect(npu_op.ofm.shape) + cur_ifm_rect = shape3d_to_rect(npu_op.ifm.shape) + padding = NpuPadding(0, 0, 0, 0) if npu_op.padding is None else npu_op.padding + blockdep = ArchitectureFeatures.MAX_BLOCKDEP + kernel = to_kernel(npu_op.kernel) + + prev_ofm_block = Block(prev_block_config.width, prev_block_config.height, prev_block_config.depth) + prev_ofm_rect = shape3d_to_rect(prev_op.ofm.shape) + # Iterate over the next BLOCKDEP inputs, checking to see if a sliding window + # of IFM area overlaps with any previous OFM block generation. + elapsed_jobs = 0 + for forward_offset in range(ArchitectureFeatures.MAX_BLOCKDEP): + # This is the IFM block we want to sample from + in_area = get_first_job_input_volume( + arch, cur_ifm_rect, cur_ofm_rect, cur_ifm_block_depth, cur_ofm_block, kernel, padding, forward_offset + ) + if in_area is None: + break + + # Try several previous-OFM blocks in the past (they still might comprise multiple IFM jobs) + outstanding_jobs = 0 + for block_offset in range(ArchitectureFeatures.MAX_BLOCKDEP): + # This is the OFM block being generated by the previous op + out_area = get_prev_job_output_volume(prev_ofm_rect, prev_ofm_block, block_offset) + if out_area is None: + break + + # Block dependency is the max number of allowed outstanding jobs + # in the pipeline. Selected by determining how many jobs occur + # in between two operators' overlapping OFM->IFM block volumes + if intersects(overlapping_fm, in_area[0], in_area[1], prev_op.ofm, out_area[0], out_area[1]): + break + # Early exit if no intersections and we've seen enough jobs in the pipeline + elif outstanding_jobs > ArchitectureFeatures.MAX_BLOCKDEP: + break + + # This OFM had this many jobs (accumulate over multiple OFM blocks) + outstanding_jobs += out_area[2] + + blockdep = min(blockdep, elapsed_jobs + outstanding_jobs) + elapsed_jobs += in_area[2] + # Early exit if no intersections and we've seen enough jobs in the pipeline + if elapsed_jobs > ArchitectureFeatures.MAX_BLOCKDEP: + break + + return blockdep |