ColossalAI/colossalai/pipeline/rpc/_pipeline_schedule.py

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from typing import List, Callable, Dict
import torch.nn as nn
from torch.futures import Future
from torch._C._distributed_rpc import PyRRef
from colossalai.pipeline.rpc._pipeline_base import PipelineEngineBase, WorkerBase, UniqueKey, Phase
# Implementation of different Pipeline schedule
# <strategy>Worker defines the worker for each stage
# <strategy>PipelineEngine is the class for use
class FillDrainWorker(WorkerBase):
def _get_work_item_key(self) -> UniqueKey:
# execute backward first (if backward phase in work_list)
num_microbatches = self.num_microbatches
if self.forward_times < num_microbatches:
target_phase = Phase.FORWARD
target_microbatch_id = self.forward_times
else:
target_phase = Phase.BACKWARD
target_microbatch_id = self.backward_times
target_key = UniqueKey(target_microbatch_id, target_phase)
with self.work_list_condition_lock:
self.work_list_condition_lock.wait_for(lambda: target_key in self.work_list)
return target_key
class FillDrainPipelineEngine(PipelineEngineBase):
def __init__(self,
module_partitions: List[nn.Module],
stage_num: int,
num_microbatches: int,
device: str,
chunk: int = 1,
criterion: Callable = None,
metric: Callable = None,
checkpoint: bool = False) -> None:
if chunk > 1:
assert num_microbatches % stage_num == 0, \
"if you use interleaving strategy, make sure 'num_microbatches' is a multiple of stage_num!"
use_1F1B = False
super().__init__(FillDrainWorker, module_partitions, stage_num, num_microbatches, device, use_1F1B, chunk,
criterion, metric, checkpoint)
class OneFOneBWorker(WorkerBase):
def _get_work_item_key(self) -> UniqueKey:
# execute backward first (if backward phase in work_list)
pp_rank = self.pp_rank
actual_stage_num = self.actual_stage_num
num_microbatches = self.num_microbatches
is_last_stage = pp_rank == actual_stage_num - 1
if self.outstanding <= self.outstanding_range[0]:
target_phase = Phase.FORWARD
target_microbatch_id = self.forward_times
elif self.outstanding >= self.outstanding_range[1]:
target_phase = Phase.BACKWARD
target_microbatch_id = self.backward_times
else:
raise ValueError("outstanding_range[1] - outstanding_range[0] must be in [0, 1]")
target_key = UniqueKey(target_microbatch_id, target_phase)
# change outstanding_range at:
# 1. forward times reach actual_stage_num, this is the end of continuous forward
# 2. forward times reach num_microbatches, this is the end of 1F1B mode
if not is_last_stage and \
target_key.phase == Phase.FORWARD:
if target_key.microbatch_id == actual_stage_num - 1:
outstanding_min = actual_stage_num - pp_rank - 1
outstanding_max = actual_stage_num - pp_rank
self.outstanding_range = (outstanding_min, outstanding_max)
elif target_key.microbatch_id == num_microbatches - 1:
self.outstanding_range = (0, 0)
with self.work_list_condition_lock:
self.work_list_condition_lock.wait_for(lambda: target_key in self.work_list)
return target_key
class OneFOneBPipelineEngine(PipelineEngineBase):
def __init__(self,
module_partitions: List[nn.Module],
stage_num: int,
num_microbatches: int,
device: str,
chunk: int = 1,
criterion: Callable = None,
metric: Callable = None,
checkpoint: bool = False) -> None:
if chunk > 1:
assert num_microbatches % stage_num == 0, \
"if you use interleaving strategy, make sure 'num_microbatches' is a multiple of stage_num!"
use_1F1B = True
super().__init__(OneFOneBWorker, module_partitions, stage_num, num_microbatches, device, use_1F1B, chunk,
criterion, metric, checkpoint)
class ChimeraWorker(WorkerBase):
def _get_producer_consumer(self) -> None:
rank = self.pp_rank
min_pp_rank = (rank // self.actual_stage_num) * self.actual_stage_num
max_pp_rank = min_pp_rank + self.actual_stage_num - 1
assert self.producer_stage_ids is None, f"all the producers of rank {rank} has been subscribed"
assert self.consumer_stage_ids is None, f"all the consumers of rank {rank} has been subscribed"
# should be aranged in order, the order of the input of current forward
self.producer_stage_ids = []
self.consumer_stage_ids = []
# Just for demo
prev_rank = rank - 1
next_rank = rank + 1
if prev_rank >= min_pp_rank:
self.producer_stage_ids.append(prev_rank)
if next_rank <= max_pp_rank:
self.consumer_stage_ids.append(next_rank)
def _get_work_item_key(self) -> UniqueKey:
pp_rank = self.pp_rank
stage_num = self.actual_stage_num
real_microbatch_num = self.num_microbatches // 2
if self.forward_times < real_microbatch_num:
if (pp_rank + 1) % stage_num == 0: # last rank
forward_blocks = self.forward_times // (self.num_microbatches // stage_num)
if forward_blocks > self.backward_times:
target_phase = Phase.BACKWARD
target_microbatch_id = self.backward_times
else:
target_phase = Phase.FORWARD
target_microbatch_id = self.forward_times
else: # others
target_phase = Phase.FORWARD
target_microbatch_id = self.forward_times
else:
target_phase = Phase.BACKWARD
target_microbatch_id = self.backward_times
# In up pipeline, microbatch_id to consume is 0, 2, 4 (2n)
# In down pipeline, microbatch_id to consume is 1, 3, 5 (2n + 1)
real_target_microbatch_id = target_microbatch_id * 2
if pp_rank >= stage_num:
real_target_microbatch_id += 1
target_key = UniqueKey(real_target_microbatch_id, target_phase)
with self.work_list_condition_lock:
self.work_list_condition_lock.wait_for(lambda: target_key in self.work_list)
return target_key
def is_first_stage(self):
return (self.pp_rank % self.actual_stage_num) == 0
def is_last_stage(self):
return (self.pp_rank % self.actual_stage_num) == self.actual_stage_num - 1
class ChimeraPipelineEngine(PipelineEngineBase):
def __init__(self,
module_partitions,
stage_num,
num_microbatches,
device: str,
criterion: Callable = None,
metric: Callable = None,
checkpoint: bool = False) -> None:
assert num_microbatches % stage_num == 0, \
"In Chimera, num_microbatches must be the multiply of stage_num!"
use_1F1B = False
chunk = 1
super().__init__(ChimeraWorker, module_partitions, stage_num, num_microbatches, device, use_1F1B, chunk,
criterion, metric, checkpoint)
def _consume_constraint(self, microbatch_id: int, forward_only: bool, ret_future: Dict[PyRRef, List[Future]],
input_worker_rrefs: List[PyRRef], output_worker_rrefs: List[PyRRef]):
pass
def _create_pp_rank_to_rpc_worker_id(self) -> None:
stage_num = self.stage_num
self.pp_rank_to_rpc_worker_id = [0] * (stage_num * 2)
for pp_rank in range(stage_num):
self.pp_rank_to_rpc_worker_id[pp_rank] = pp_rank
self.pp_rank_to_rpc_worker_id[pp_rank + stage_num] = stage_num - pp_rank - 1
def _create_pp_rank_to_module_partition_id(self) -> None:
stage_num = self.stage_num
self.pp_rank_to_module_partition_id = [0] * (stage_num * 2)
for pp_rank in range(stage_num):
self.pp_rank_to_module_partition_id[pp_rank] = pp_rank
self.pp_rank_to_module_partition_id[pp_rank + stage_num] = pp_rank
def _create_ret_future(self, output_pp_ranks: List[int]) -> Dict[int, List[Future]]:
num_microbatches = self.num_microbatches
stage_num = self.stage_num
up_ret_future = {pp_rank: [None] * num_microbatches for pp_rank in output_pp_ranks}
down_ret_future = {pp_rank + stage_num: [None] * num_microbatches for pp_rank in output_pp_ranks}
# merge up and down
return {**up_ret_future, **down_ret_future}
def _set_input(self, input_pp_ranks: List[int], microbatch_id: int, microbatch, forward_only: bool):
# offset is 0 for all the ranks in up pipeline
# offset is stage_num for all the ranks in down pipeline
offset = (microbatch_id % 2) * self.stage_num
for pp_rank in input_pp_ranks:
worker_rref = self.pp_rank_to_worker_rref[pp_rank + offset]
worker_rref.remote().set_input(microbatch_id, microbatch, forward_only)
def _set_labels(self, output_pp_ranks: List[int], microbatch_id: int, microlabels):
# offset is 0 for all the ranks in up pipeline
# offset is stage_num for all the ranks in down pipeline
offset = (microbatch_id % 2) * self.stage_num
for pp_rank in output_pp_ranks:
worker_rref = self.pp_rank_to_worker_rref[pp_rank + offset]
worker_rref.remote().set_labels(microbatch_id, microlabels)
def _subscribe_forward(self, microbatch_id: int, output_pp_ranks: List[int], ret_future: Dict[int, List[Future]]):
key = UniqueKey(microbatch_id, Phase.FORWARD)
offset = (microbatch_id % 2) * self.stage_num
for pp_rank in output_pp_ranks:
worker_rref = self.pp_rank_to_worker_rref[pp_rank + offset]
ret_future[pp_rank + offset][microbatch_id] = worker_rref.rpc_async().get_output_by_key(key)
def _ensure_backward(self, forward_only: bool, input_pp_ranks: List[int]):
stage_num = self.stage_num
num_microbatches = self.num_microbatches
if not forward_only:
for pp_rank in input_pp_ranks:
up_last_microbatch_id = num_microbatches - 2
down_last_microbatch_id = num_microbatches - 1
up_worker_rref = self.pp_rank_to_worker_rref[pp_rank]
down_worker_rref = self.pp_rank_to_worker_rref[pp_rank + stage_num]
up_key = UniqueKey(up_last_microbatch_id, Phase.BACKWARD)
down_key = UniqueKey(down_last_microbatch_id, Phase.BACKWARD)
up_worker_rref.rpc_sync().get_output_by_key(up_key)
down_worker_rref.rpc_sync().get_output_by_key(down_key)
def _collect_forward_result(self, output_pp_ranks: List[int], ret_future: Dict[PyRRef, List[Future]]):
"""Logic of collection of forward in Chimera.
Currently, only one input one output model is supported
"""
stage_num = self.stage_num
forward_result = []
for pp_rank in output_pp_ranks:
worker_forward_result = [None] * self.num_microbatches
for microbatch_id in range(self.num_microbatches):
offset = (microbatch_id % 2) * stage_num
ret = ret_future[pp_rank + offset][microbatch_id].wait()
worker_forward_result[microbatch_id] = ret
worker_forward_result = list(zip(*worker_forward_result))
forward_result.extend(worker_forward_result)
return forward_result