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ColossalAI/colossalai/auto_parallel/meta_profiler/meta_registry/where.py

61 lines
2.9 KiB

from typing import List, Tuple
import torch
from colossalai._analyzer._subclasses.flop_tensor import flop_mapping
from colossalai._analyzer.fx.node_util import compute_size_in_bytes as activation_size
from colossalai.auto_parallel.tensor_shard.sharding_strategy import MemoryCost, OperationDataType, TrainCycleItem
from ..registry import meta_register
__all__ = ["where_meta_info"]
@meta_register.register(torch.where)
def where_meta_info(*args, **kwargs) -> Tuple[TrainCycleItem, TrainCycleItem, List[torch.Tensor]]:
"""torch.where meta information generator
Returns:
Tuple[TrainCycleItem, TrainCycleItem, List[torch.Tensor]]: compute cost, memory cost and forward inputs
"""
condition_tensor, x_tensor, y_tensor, output_tensor = [arg.data for arg in args]
# compute cost
fwd_compute_cost = 0
# if we need to broadcast the condition tensor, during backward we need to do a reduce_sum
bwd_compute_cost = 0
if x_tensor.shape != output_tensor.shape:
bwd_compute_cost += flop_mapping[torch.ops.aten.sum.dim_IntList]([output_tensor], [x_tensor])
if y_tensor.shape != output_tensor.shape:
bwd_compute_cost += flop_mapping[torch.ops.aten.sum.dim_IntList]([output_tensor], [y_tensor])
compute_cost = TrainCycleItem(fwd=fwd_compute_cost, bwd=bwd_compute_cost, total=fwd_compute_cost + bwd_compute_cost)
# memory cost
# during the forward phase, torch.where will allocate memory for output tensor and condition tensor
# during the backward phase, torch.where will allocate temp memory which is 3 times as output tensor, then generate
# gradient matrix for input x and input y, remove the temp memory and condition tensor generated in forward phase
# NOTE: currently in SPMD solver we always believe that there will be a new input tensor created in forward
fwd_mem_cost = MemoryCost(activation=activation_size([condition_tensor, x_tensor, y_tensor, output_tensor]))
bwd_mem_cost = MemoryCost(activation=activation_size([x_tensor, y_tensor]) - activation_size([condition_tensor]),
parameter=0,
temp=activation_size([output_tensor]) * 3 + activation_size([condition_tensor]) -
activation_size([x_tensor, y_tensor]),
buffer=0)
total_mem_cost = MemoryCost(activation=fwd_mem_cost.activation + bwd_mem_cost.activation,
parameter=fwd_mem_cost.parameter + bwd_mem_cost.parameter,
temp=fwd_mem_cost.temp + bwd_mem_cost.temp,
buffer=fwd_mem_cost.buffer + bwd_mem_cost.buffer)
memory_cost = TrainCycleItem(fwd=fwd_mem_cost, bwd=bwd_mem_cost, total=total_mem_cost)
# store fwd_in, fwd_buffer, fwd_out
fwd_in = [condition_tensor]
fwd_buffer = []
fwd_out = [output_tensor]
return compute_cost, memory_cost, fwd_in, fwd_buffer, fwd_out