Add memory cutoff on ActivationBalancer and Whiten

This commit is contained in:
Daniel Povey 2022-12-17 16:20:15 +08:00
parent 96daf7a00f
commit 29df07ba2c

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@ -230,6 +230,41 @@ def random_cast_to_half(x: Tensor,
return torch.where(is_too_small, random_val, x).to(torch.float16)
class CutoffEstimator:
"""
Estimates cutoffs of an arbitrary numerical quantity such that a specified
proportion of items will be above the cutoff on average.
p is the proportion of items that should be above the cutoff.
"""
def __init__(self, p: float):
self.p = p
# total count of items
self.count = 0
# total count of items that were above the cutoff
self.count_above = 0
# initial cutoff value
self.cutoff = 0
def __call__(self, x: float) -> bool:
"""
Returns true if x is above the cutoff.
"""
ans = (x > self.cutoff)
self.count += 1
if ans:
self.count_above += 1
cur_p = self.count_above / self.count
print(f"cur_p = {cur_p}, cutoff = {self.cutoff}")
delta_p = cur_p - self.p
if (delta_p > 0) == ans:
q = abs(delta_p)
self.cutoff = x * q + self.cutoff * (1-q)
return ans
class CachingEvalFunction(torch.autograd.Function):
# @custom_fwd and @custom_bwd related to automatic mixed precision (amp) an ensure
# that the backward path runs with the same autocast context as the forward pass.
@ -605,6 +640,9 @@ class ActivationBalancer(torch.nn.Module):
if prob is None:
prob = ScheduledFloat((0.0, 0.4), (8000.0, 0.1), default=0.4)
self.prob = prob
# 10% of the time we will return and do nothing because memory usage
# is too high.
self.mem_cutoff = CutoffEstimator(0.1)
# actually self.num_channels is no longer needed except for an assertion.
self.num_channels = num_channels
@ -618,11 +656,9 @@ class ActivationBalancer(torch.nn.Module):
self.scale_gain_factor = scale_gain_factor
def forward(self, x: Tensor) -> Tensor:
if torch.jit.is_scripting() or not x.requires_grad:
if (torch.jit.is_scripting() or not x.requires_grad or
(x.is_cuda and self.mem_cutoff(torch.cuda.memory_allocated()))):
return _no_op(x)
prob = float(self.prob)
@ -776,7 +812,7 @@ class Whiten(nn.Module):
num_groups: int,
whitening_limit: FloatLike,
prob: Union[float, Tuple[float,float]],
grad_scale: float):
grad_scale: FloatLike):
"""
Args:
num_groups: the number of groups to divide the channel dim into before
@ -801,6 +837,12 @@ class Whiten(nn.Module):
assert grad_scale >= 0
self.num_groups = num_groups
self.whitening_limit = whitening_limit
self.grad_scale = grad_scale
# 10% of the time we will return and do nothing because memory usage
# is too high.
self.mem_cutoff = CutoffEstimator(0.1)
if isinstance(prob, float):
assert 0 < prob <= 1
self.prob = prob
@ -809,7 +851,6 @@ class Whiten(nn.Module):
assert 0 < self.min_prob < self.max_prob <= 1
self.prob = self.max_prob
self.name = None # will be set in training loop
self.grad_scale = grad_scale
def forward(self,
x: Tensor) -> Tensor:
@ -829,7 +870,9 @@ class Whiten(nn.Module):
you use the returned value, or the graph will be freed
and nothing will happen in backprop.
"""
if not x.requires_grad or random.random() > self.prob or self.grad_scale == 0:
grad_scale = float(self.grad_scale)
if (not x.requires_grad or random.random() > self.prob or grad_scale == 0
or (x.is_cuda and self.mem_cutoff(torch.cuda.memory_allocated()))):
return _no_op(x)
else:
whitening_limit = float(self.whitening_limit)
@ -845,7 +888,7 @@ class Whiten(nn.Module):
return WhiteningPenaltyFunction.apply(x,
self.num_groups,
whitening_limit,
self.grad_scale,
grad_scale,
self.name)