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Update formula for 1F1B-interleave-overlap.
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# PP schedule config
from src.execution_model import ScheduleConfig
from src.strategies import generate_1f1b_interleave_overlap_schedule, generate_dualpipe_v_schedule
p = 4 # PP size
v = 2 # number of virtual stages
m = 16 # total microbatches
# stage time config
F = 2.0 # forward time in one PP rank for all stages
W = 2.0 # backward_W time in one PP rank for all stages
D = 2.0 # backward_D time in one PP rank for all stages
B = W + D # backward time in one PP rank for all stages
FwB = 5.5 # overlapped forward backward time in one PP rank for all stages
op_times = {
"forward": F,
"backward": B,
"backward_D": D,
"backward_W": W,
"overlapped_forward_backward": FwB
}
def dualpipe_v_execution_time_by_formula():
# Formula from the image
item_1 = ((p - 1) / 2) * F
item_2 = (p + 0.5) * F + (p / 2 + 1) * B
item_3 = (m - (p / 2 + 1)) * FwB
print(f"item_1: {item_1}, item_2: {item_2}, item_3: {item_3}")
total_time = item_1 + item_2 + item_3
return total_time
def dualpipe_v_execution_time_by_formula_detailed():
# Correct formula
local_F = F / 2
local_B = B / 2
local_D = D / 2
local_W = W / 2
local_FwB = FwB / 2
forward_bubble = (p - 1) * local_F # forward bubble
forward_time = 2 * p * local_F
overlapped_time = (2 * (m-p)-1) * local_FwB + (p-1) * local_FwB
backward_time = (2*p-1) * local_D + local_W
other_time = 2 * local_B + local_F
active_time = (2 * (m-p)-1) * local_FwB + (2*p+1) * (local_F + local_B)
total_time = forward_bubble + forward_time + overlapped_time + backward_time + other_time
bubble_time = total_time - active_time
assert bubble_time == (p-1)*(local_FwB + local_B - 3*local_W)
return total_time
def dualpipe_v_execution_time_by_emulate():
op_times_per_stage = {
"forward": F / 2,
"backward": B / 2,
"backward_D": D / 2,
"backward_W": W / 2,
"overlapped_forward_backward": FwB / 2
}
print(f"op_times_per_stage: {op_times_per_stage}")
dualpipe_schedule_config = ScheduleConfig(
num_devices=p,
num_stages=p*2,
num_batches=m,
p2p_latency=0.0,
op_times=op_times_per_stage,
split_backward=True,
placement_strategy="dualpipe_v",
)
dual_pipe_schedule = generate_dualpipe_v_schedule(dualpipe_schedule_config)
dual_pipe_schedule.execute()
return dual_pipe_schedule.get_total_execution_time()
def overlap_1f1b_execution_time_by_emulate():
op_times_per_stage = {
"forward": F / v,
"backward": B / v,
"backward_D": D / v,
"backward_W": W / v,
"overlapped_forward_backward": FwB / v
}
overlap_1f1b_schedule_config = ScheduleConfig(
num_devices=p,
num_stages=p*v,
num_batches=m,
p2p_latency=0.0,
op_times=op_times_per_stage,
split_backward=False,
placement_strategy="interleave",
)
overlap_1f1b_schedule = generate_1f1b_interleave_overlap_schedule(overlap_1f1b_schedule_config)
overlap_1f1b_schedule.execute()
return overlap_1f1b_schedule.get_total_execution_time()
def overlap_1f1b_execution_time_by_formula():
forward_bubble = (p-1) * F / v
backward_bubble = (p-1) * B / v
non_overlapped_batches = p*(v - 1) + 1
forward_backward_time = non_overlapped_batches * (F + B) / v
overlapped_time = (m*v - non_overlapped_batches) * FwB / v
total_time = forward_bubble + backward_bubble + forward_backward_time + overlapped_time
return total_time
print(f"DualPipe-V by emulate: {dualpipe_v_execution_time_by_emulate()}")
print(f"DualPipe-V by formula detailed: {dualpipe_v_execution_time_by_formula_detailed()}")
print(f"Overlap-1f1b by emulate: {overlap_1f1b_execution_time_by_emulate()}")
print(f"Overlap-1f1b by formula: {overlap_1f1b_execution_time_by_formula()}")