"""
B-ASIC Schedule Module.
Contains the schedule class for scheduling operations in an SFG.
"""
import io
import sys
from collections import defaultdict
from typing import Dict, List, Optional, Tuple
import matplotlib.pyplot as plt
from matplotlib.lines import Line2D
from matplotlib.patches import PathPatch, Polygon
from matplotlib.path import Path
from matplotlib.ticker import MaxNLocator
import numpy as np
from b_asic import OutputPort, Signal
from b_asic._preferences import (
EXECUTION_TIME_COLOR,
LATENCY_COLOR,
SIGNAL_COLOR,
SIGNAL_LINEWIDTH,
)
from b_asic.graph_component import GraphID
from b_asic.process import MemoryVariable, Process
from b_asic.signal_flow_graph import SFG
from b_asic.special_operations import Delay, Output
_EXECUTION_TIME_COLOR = tuple(c / 255 for c in EXECUTION_TIME_COLOR)
_LATENCY_COLOR = tuple(c / 255 for c in LATENCY_COLOR)
_SIGNAL_COLOR = tuple(c / 255 for c in SIGNAL_COLOR)
class Schedule:
"""Schedule of an SFG with scheduled Operations."""
_sfg: SFG
_start_times: Dict[GraphID, int]
_laps: Dict[GraphID, List[int]]
_schedule_time: int
_cyclic: bool
def __init__(
self,
sfg: SFG,
schedule_time: Optional[int] = None,
cyclic: bool = False,
scheduling_alg: str = "ASAP",
):
"""Construct a Schedule from an SFG."""
self._sfg = sfg
self._start_times = {}
self._laps = defaultdict(lambda: 0)
self._cyclic = cyclic
if scheduling_alg == "ASAP":
self._schedule_asap()
else:
raise NotImplementedError(
f"No algorithm with name: {scheduling_alg} defined."
)
max_end_time = self.get_max_end_time()
if schedule_time is None:
self._schedule_time = max_end_time
elif schedule_time < max_end_time:
raise ValueError(
f"Too short schedule time. Minimum is {max_end_time}."
)
else:
self._schedule_time = schedule_time
def start_time_of_operation(self, op_id: GraphID) -> int:
"""Get the start time of the operation with the specified by the op_id.
"""
assert (
op_id in self._start_times
), "No operation with the specified op_id in this schedule."
return self._start_times[op_id]
def get_max_end_time(self) -> int:
"""Returns the current maximum end time among all operations."""
max_end_time = 0
for op_id, op_start_time in self._start_times.items():
op = self._sfg.find_by_id(op_id)
for outport in op.outputs:
max_end_time = max(
max_end_time, op_start_time + outport.latency_offset
)
return max_end_time
def forward_slack(self, op_id: GraphID) -> int:
assert (
op_id in self._start_times
), "No operation with the specified op_id in this schedule."
slack = sys.maxsize
output_slacks = self._forward_slacks(op_id)
# Make more pythonic
for signal_slacks in output_slacks.values():
for signal_slack in signal_slacks.values():
slack = min(slack, signal_slack)
return slack
def _forward_slacks(
self, op_id: GraphID
) -> Dict["OutputPort", Dict["Signal", int]]:
ret = {}
start_time = self._start_times[op_id]
op = self._sfg.find_by_id(op_id)
for output_port in op.outputs:
output_slacks = {}
available_time = start_time + output_port.latency_offset
for signal in output_port.signals:
usage_time = (
signal.destination.latency_offset
+ self._start_times[signal.destination.operation.graph_id]
+ self._schedule_time * self._laps[signal.graph_id]
)
output_slacks[signal] = usage_time - available_time
ret[output_port] = output_slacks
return ret
def backward_slack(self, op_id: GraphID) -> int:
assert (
op_id in self._start_times
), "No operation with the specified op_id in this schedule."
slack = sys.maxsize
input_slacks = self._backward_slacks(op_id)
# Make more pythonic
for signal_slacks in input_slacks.values():
for signal_slack in signal_slacks.values():
slack = min(slack, signal_slack)
return slack
def _backward_slacks(
self, op_id: GraphID
) -> Dict["OutputPort", Dict["Signal", int]]:
ret = {}
start_time = self._start_times[op_id]
op = self._sfg.find_by_id(op_id)
for input_port in op.inputs:
input_slacks = {}
usage_time = start_time + input_port.latency_offset
for signal in input_port.signals:
available_time = (
signal.source.latency_offset
+ self._start_times[signal.source.operation.graph_id]
- self._schedule_time * self._laps[signal.graph_id]
)
input_slacks[signal] = usage_time - available_time
ret[input_port] = input_slacks
return ret
def slacks(self, op_id: GraphID) -> Tuple[int, int]:
assert (
op_id in self._start_times
), "No operation with the specified op_id in this schedule."
return self.backward_slack(op_id), self.forward_slack(op_id)
def print_slacks(self) -> None:
raise NotImplementedError
def set_schedule_time(self, time: int) -> "Schedule":
assert self.get_max_end_time() <= time, "New schedule time to short."
self._schedule_time = time
return self
@property
def sfg(self) -> SFG:
return self._sfg
@property
def start_times(self) -> Dict[GraphID, int]:
return self._start_times
@property
def laps(self) -> Dict[GraphID, List[int]]:
return self._laps
@property
def schedule_time(self) -> int:
return self._schedule_time
@property
def cyclic(self) -> bool:
return self._cyclic
def increase_time_resolution(self, factor: int) -> "Schedule":
"""
Increase time resolution for a schedule.
Parameters
==========
factor : int
The time resolution increment.
"""
self._start_times = {
k: factor * v for k, v in self._start_times.items()
}
for op_id in self._start_times:
self._sfg.find_by_id(op_id)._increase_time_resolution(factor)
self._schedule_time *= factor
return self
def _get_all_times(self) -> List[int]:
"""
Return a list of all times for the schedule. Used to check how the
resolution can be modified.
"""
# Local values
ret = [self._schedule_time, *self._start_times.values()]
# Loop over operations
for op_id in self._start_times:
op = self._sfg.find_by_id(op_id)
ret += [op.execution_time, *op.latency_offsets.values()]
# Remove not set values (None)
ret = [v for v in ret if v is not None]
return ret
def get_possible_time_resolution_decrements(self) -> List[int]:
"""Return a list with possible factors to reduce time resolution."""
vals = self._get_all_times()
maxloop = min(val for val in vals if val)
if maxloop <= 1:
return [1]
ret = [1]
for candidate in range(2, maxloop + 1):
if not any(val % candidate for val in vals):
ret.append(candidate)
return ret
def decrease_time_resolution(self, factor: int) -> "Schedule":
"""
Decrease time resolution for a schedule.
Parameters
==========
factor : int
The time resolution decrement.
"""
possible_values = self.get_possible_time_resolution_decrements()
if factor not in possible_values:
raise ValueError(
f"Not possible to decrease resolution with {factor}. Possible"
f" values are {possible_values}"
)
self._start_times = {
k: v // factor for k, v in self._start_times.items()
}
for op_id in self._start_times:
self._sfg.find_by_id(op_id)._decrease_time_resolution(factor)
self._schedule_time = self._schedule_time // factor
return self
def move_operation(self, op_id: GraphID, time: int) -> "Schedule":
assert (
op_id in self._start_times
), "No operation with the specified op_id in this schedule."
(backward_slack, forward_slack) = self.slacks(op_id)
if not -backward_slack <= time <= forward_slack:
raise ValueError
tmp_start = self._start_times[op_id] + time
new_start = tmp_start % self._schedule_time
# Update input laps
input_slacks = self._backward_slacks(op_id)
for in_port, signal_slacks in input_slacks.items():
tmp_usage = tmp_start + in_port.latency_offset
new_usage = tmp_usage % self._schedule_time
for signal, signal_slack in signal_slacks.items():
new_slack = signal_slack + time
old_laps = self._laps[signal.graph_id]
tmp_prev_available = tmp_usage - new_slack
prev_available = tmp_prev_available % self._schedule_time
laps = new_slack // self._schedule_time
if new_usage < prev_available:
laps += 1
print(
[
signal_slack,
new_slack,
old_laps,
laps,
new_usage,
prev_available,
tmp_usage,
tmp_prev_available,
]
)
self._laps[signal.graph_id] = laps
# Update output laps
output_slacks = self._forward_slacks(op_id)
for out_port, signal_slacks in output_slacks.items():
tmp_available = tmp_start + out_port.latency_offset
new_available = tmp_available % self._schedule_time
for signal, signal_slack in signal_slacks.items():
new_slack = signal_slack - time
tmp_next_usage = tmp_available + new_slack
next_usage = tmp_next_usage % self._schedule_time
laps = new_slack // self._schedule_time
if next_usage < new_available:
laps += 1
if new_available == 0 and new_slack > 0:
laps += 1
self._laps[signal.graph_id] = laps
# Set new start time
self._start_times[op_id] = new_start
return self
def _remove_delays(self) -> None:
delay_list = self._sfg.find_by_type_name(Delay.type_name())
while delay_list:
delay_op = delay_list[0]
delay_input_id = delay_op.input(0).signals[0].graph_id
delay_output_ids = [
sig.graph_id for sig in delay_op.output(0).signals
]
self._sfg = self._sfg.remove_operation(delay_op.graph_id)
for output_id in delay_output_ids:
self._laps[output_id] += 1 + self._laps[delay_input_id]
del self._laps[delay_input_id]
delay_list = self._sfg.find_by_type_name(Delay.type_name())
def _schedule_asap(self) -> None:
pl = self._sfg.get_precedence_list()
if len(pl) < 2:
print("Empty signal flow graph cannot be scheduled.")
return
non_schedulable_ops = set()
for outport in pl[0]:
op = outport.operation
if op.type_name() not in [Delay.type_name()]:
if op.graph_id not in self._start_times:
# Set start time of all operations in the first iter to 0
self._start_times[op.graph_id] = 0
else:
non_schedulable_ops.add(op.graph_id)
for outport in pl[1]:
op = outport.operation
if op.graph_id not in self._start_times:
# Set start time of all operations in the first iter to 0
self._start_times[op.graph_id] = 0
for outports in pl[2:]:
for outport in outports:
op = outport.operation
if op.graph_id not in self._start_times:
# Schedule the operation if it doesn't have a start time yet.
op_start_time = 0
for inport in op.inputs:
assert (
len(inport.signals) == 1
), "Error in scheduling, dangling input port detected."
assert inport.signals[0].source is not None, (
"Error in scheduling, signal with no source"
" detected."
)
source_port = inport.signals[0].source
source_end_time = None
if (
source_port.operation.graph_id
in non_schedulable_ops
):
source_end_time = 0
else:
source_op_time = self._start_times[
source_port.operation.graph_id
]
assert source_port.latency_offset is not None, (
f"Output port: {source_port.index} of"
" operation: "
f" {source_port.operation.graph_id} has no"
" latency-offset."
)
assert inport.latency_offset is not None, (
f"Input port: {inport.index} of operation: "
" "
f" {inport.operation.graph_id} has no"
" latency-offset."
)
source_end_time = (
source_op_time + source_port.latency_offset
)
op_start_time_from_in = (
source_end_time - inport.latency_offset
)
op_start_time = max(
op_start_time, op_start_time_from_in
)
self._start_times[op.graph_id] = op_start_time
for output in self._sfg.find_by_type_name(Output.type_name()):
source_port = output.inputs[0].signals[0].source
if source_port.operation.graph_id in non_schedulable_ops:
self._start_times[output.graph_id] = 0
else:
self._start_times[output.graph_id] = (
self._start_times[source_port.operation.graph_id]
+ source_port.latency_offset
)
self._remove_delays()
def _get_memory_variables_list(self) -> List['Process']:
ret = []
for op_id, start_time in self._start_times.items():
slacks = self._forward_slacks(op_id)
for outport, signals in slacks.items():
reads = {
signal.destination: slack
for signal, slack in signals.items()
}
ret.append(
MemoryVariable(
start_time + outport.latency_offset, outport, reads
)
)
return ret
def _plot_schedule(self, ax):
line_cache = []
def _draw_arrow(start, end, name="", laps=0):
if end[0] < start[0] or laps > 0: # Wrap around
if start not in line_cache:
line = Line2D(
[start[0], self._schedule_time + 0.2],
[start[1], start[1]],
color=_SIGNAL_COLOR,
lw=SIGNAL_LINEWIDTH,
)
ax.add_line(line)
ax.text(
self._schedule_time + 0.2,
start[1],
name,
verticalalignment="center",
)
line = Line2D(
[-0.2, end[0]],
[end[1], end[1]],
color=_SIGNAL_COLOR,
lw=SIGNAL_LINEWIDTH,
)
ax.add_line(line)
ax.text(
-0.2,
end[1],
f"{name}: {laps}",
verticalalignment="center",
horizontalalignment="right",
)
line_cache.append(start)
elif end[0] == start[0]:
p = Path(
[
start,
[start[0] + 0.2, start[1]],
[start[0] + 0.2, (start[1] + end[1]) / 2],
[start[0], (start[1] + end[1]) / 2],
[start[0] - 0.2, (start[1] + end[1]) / 2],
[start[0] - 0.2, end[1]],
end,
],
[
Path.MOVETO,
Path.CURVE4,
Path.CURVE4,
Path.CURVE4,
Path.CURVE4,
Path.CURVE4,
Path.CURVE4,
],
)
pp = PathPatch(
p,
fc='none',
ec=_SIGNAL_COLOR,
lw=SIGNAL_LINEWIDTH,
zorder=10,
)
ax.add_patch(pp)
else:
p = Path(
[
start,
[(start[0] + end[0]) / 2, start[1]],
[(start[0] + end[0]) / 2, end[1]],
end,
],
[Path.MOVETO, Path.CURVE4, Path.CURVE4, Path.CURVE4],
)
pp = PathPatch(
p,
fc='none',
ec=_SIGNAL_COLOR,
lw=SIGNAL_LINEWIDTH,
zorder=10,
)
ax.add_patch(pp)
def _draw_offset_arrow(
start, end, start_offset, end_offset, name="", laps=0
):
_draw_arrow(
[start[0] + start_offset[0], start[1] + start_offset[1]],
[end[0] + end_offset[0], end[1] + end_offset[1]],
name=name,
laps=laps,
)
ypos = 0.5
ytickpositions = []
yticklabels = []
ax.set_axisbelow(True)
ax.grid()
ypositions = {}
for op_id, op_start_time in self._start_times.items():
op = self._sfg.find_by_id(op_id)
# Rewrite to make better use of NumPy
latency_coords, execution_time_coords = op.get_plot_coordinates()
_x, _y = zip(*latency_coords)
x = np.array(_x)
y = np.array(_y)
xy = np.stack((x + op_start_time, y + ypos))
p = Polygon(xy.T, fc=_LATENCY_COLOR)
ax.add_patch(p)
if execution_time_coords:
_x, _y = zip(*execution_time_coords)
x = np.array(_x)
y = np.array(_y)
ax.plot(
x + op_start_time,
y + ypos,
color=_EXECUTION_TIME_COLOR,
linewidth=3,
)
ytickpositions.append(ypos + 0.5)
yticklabels.append(self._sfg.find_by_id(op_id).name)
ypositions[op_id] = ypos
ypos += 1.5
for op_id, op_start_time in self._start_times.items():
op = self._sfg.find_by_id(op_id)
_, out_coords = op.get_io_coordinates()
source_ypos = ypositions[op_id]
for output_port in op.outputs:
for output_signal in output_port.signals:
dest_op = output_signal.destination.operation
dest_start_time = self._start_times[dest_op.graph_id]
dest_ypos = ypositions[dest_op.graph_id]
(
dest_in_coords,
_,
) = (
output_signal.destination.operation.get_io_coordinates()
)
_draw_offset_arrow(
out_coords[output_port.index],
dest_in_coords[output_signal.destination.index],
[op_start_time, source_ypos],
[dest_start_time, dest_ypos],
name=op_id,
laps=self._laps[output_signal.graph_id],
)
ax.set_yticks(ytickpositions)
ax.set_yticklabels(yticklabels)
ax.axis([-1, self._schedule_time + 1, 0, ypos])
ax.xaxis.set_major_locator(MaxNLocator(integer=True))
ax.add_line(Line2D([0, 0], [0, ypos], linestyle="--", color="black"))
ax.add_line(
Line2D(
[self._schedule_time, self._schedule_time],
[0, ypos],
linestyle="--",
color="black",
)
)
def plot_schedule(self) -> None:
self._get_figure().show()
def _get_figure(self):
fig, ax = plt.subplots()
self._plot_schedule(ax)
return fig
def _repr_svg_(self):
fig, ax = plt.subplots()
self._plot_schedule(ax)
f = io.StringIO()
fig.savefig(f, format="svg")
return f.getvalue()