Shitao-OmniGen-v1 / OmniGen /scheduler.py
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from tqdm import tqdm
from typing import Optional, Dict, Any, Tuple, List
import gc
import torch
from transformers.cache_utils import Cache, DynamicCache, OffloadedCache
class OmniGenCache(DynamicCache):
def __init__(self,
num_tokens_for_img: int, offload_kv_cache: bool=False) -> None:
if not torch.cuda.is_available():
raise RuntimeError("OffloadedCache can only be used with a GPU")
super().__init__()
self.original_device = []
self.prefetch_stream = torch.cuda.Stream()
self.num_tokens_for_img = num_tokens_for_img
self.offload_kv_cache = offload_kv_cache
def prefetch_layer(self, layer_idx: int):
"Starts prefetching the next layer cache"
if layer_idx < len(self):
with torch.cuda.stream(self.prefetch_stream):
# Prefetch next layer tensors to GPU
device = self.original_device[layer_idx]
self.key_cache[layer_idx] = self.key_cache[layer_idx].to(device, non_blocking=True)
self.value_cache[layer_idx] = self.value_cache[layer_idx].to(device, non_blocking=True)
def evict_previous_layer(self, layer_idx: int):
"Moves the previous layer cache to the CPU"
if len(self) > 2:
# We do it on the default stream so it occurs after all earlier computations on these tensors are done
if layer_idx == 0:
prev_layer_idx = -1
else:
prev_layer_idx = (layer_idx - 1) % len(self)
self.key_cache[prev_layer_idx] = self.key_cache[prev_layer_idx].to("cpu", non_blocking=True)
self.value_cache[prev_layer_idx] = self.value_cache[prev_layer_idx].to("cpu", non_blocking=True)
def __getitem__(self, layer_idx: int) -> List[Tuple[torch.Tensor]]:
"Gets the cache for this layer to the device. Prefetches the next and evicts the previous layer."
if layer_idx < len(self):
if self.offload_kv_cache:
# Evict the previous layer if necessary
torch.cuda.current_stream().synchronize()
self.evict_previous_layer(layer_idx)
# Load current layer cache to its original device if not already there
original_device = self.original_device[layer_idx]
# self.prefetch_stream.synchronize(original_device)
torch.cuda.synchronize(self.prefetch_stream)
key_tensor = self.key_cache[layer_idx]
value_tensor = self.value_cache[layer_idx]
# Prefetch the next layer
self.prefetch_layer((layer_idx + 1) % len(self))
else:
key_tensor = self.key_cache[layer_idx]
value_tensor = self.value_cache[layer_idx]
return (key_tensor, value_tensor)
else:
raise KeyError(f"Cache only has {len(self)} layers, attempted to access layer with index {layer_idx}")
def update(
self,
key_states: torch.Tensor,
value_states: torch.Tensor,
layer_idx: int,
cache_kwargs: Optional[Dict[str, Any]] = None,
) -> Tuple[torch.Tensor, torch.Tensor]:
"""
Updates the cache with the new `key_states` and `value_states` for the layer `layer_idx`.
Parameters:
key_states (`torch.Tensor`):
The new key states to cache.
value_states (`torch.Tensor`):
The new value states to cache.
layer_idx (`int`):
The index of the layer to cache the states for.
cache_kwargs (`Dict[str, Any]`, `optional`):
Additional arguments for the cache subclass. No additional arguments are used in `OffloadedCache`.
Return:
A tuple containing the updated key and value states.
"""
# Update the cache
if len(self.key_cache) < layer_idx:
raise ValueError("OffloadedCache does not support model usage where layers are skipped. Use DynamicCache.")
elif len(self.key_cache) == layer_idx:
# only cache the states for condition tokens
key_states = key_states[..., :-(self.num_tokens_for_img+1), :]
value_states = value_states[..., :-(self.num_tokens_for_img+1), :]
# Update the number of seen tokens
if layer_idx == 0:
self._seen_tokens += key_states.shape[-2]
self.key_cache.append(key_states)
self.value_cache.append(value_states)
self.original_device.append(key_states.device)
if self.offload_kv_cache:
self.evict_previous_layer(layer_idx)
return self.key_cache[layer_idx], self.value_cache[layer_idx]
else:
# only cache the states for condition tokens
key_tensor, value_tensor = self[layer_idx]
k = torch.cat([key_tensor, key_states], dim=-2)
v = torch.cat([value_tensor, value_states], dim=-2)
return k, v
class OmniGenScheduler:
def __init__(self, num_steps: int=50, time_shifting_factor: int=1):
self.num_steps = num_steps
self.time_shift = time_shifting_factor
t = torch.linspace(0, 1, num_steps+1)
t = t / (t + time_shifting_factor - time_shifting_factor * t)
self.sigma = t
def crop_kv_cache(self, past_key_values, num_tokens_for_img):
# return
crop_past_key_values = ()
for layer_idx in range(len(past_key_values)):
key_states, value_states = past_key_values[layer_idx][:2]
crop_past_key_values += ((key_states[..., :-(num_tokens_for_img+1), :], value_states[..., :-(num_tokens_for_img+1), :], ),)
# return crop_past_key_values
return DynamicCache.from_legacy_cache(crop_past_key_values)
def crop_position_ids_for_cache(self, position_ids, num_tokens_for_img):
if isinstance(position_ids, list):
for i in range(len(position_ids)):
position_ids[i] = position_ids[i][:, -(num_tokens_for_img+1):]
else:
position_ids = position_ids[:, -(num_tokens_for_img+1):]
return position_ids
def crop_attention_mask_for_cache(self, attention_mask, num_tokens_for_img):
if isinstance(attention_mask, list):
return [x[..., -(num_tokens_for_img+1):, :] for x in attention_mask]
return attention_mask[..., -(num_tokens_for_img+1):, :]
def crop_cache(self, cache, num_tokens_for_img):
for i in range(len(cache.key_cache)):
cache.key_cache[i] = cache.key_cache[i][..., :-(num_tokens_for_img+1), :]
cache.value_cache[i] = cache.value_cache[i][..., :-(num_tokens_for_img+1), :]
return cache
def __call__(self, z, func, model_kwargs, use_kv_cache: bool=True, offload_kv_cache: bool=True):
num_tokens_for_img = z.size(-1)*z.size(-2) // 4
if isinstance(model_kwargs['input_ids'], list):
cache = [OmniGenCache(num_tokens_for_img, offload_kv_cache) for _ in range(len(model_kwargs['input_ids']))] if use_kv_cache else None
else:
cache = OmniGenCache(num_tokens_for_img, offload_kv_cache) if use_kv_cache else None
results = {}
for i in tqdm(range(self.num_steps)):
timesteps = torch.zeros(size=(len(z), )).to(z.device) + self.sigma[i]
pred, cache = func(z, timesteps, past_key_values=cache, **model_kwargs)
sigma_next = self.sigma[i+1]
sigma = self.sigma[i]
z = z + (sigma_next - sigma) * pred
if i == 0 and use_kv_cache:
num_tokens_for_img = z.size(-1)*z.size(-2) // 4
if isinstance(cache, list):
model_kwargs['input_ids'] = [None] * len(cache)
else:
model_kwargs['input_ids'] = None
model_kwargs['position_ids'] = self.crop_position_ids_for_cache(model_kwargs['position_ids'], num_tokens_for_img)
model_kwargs['attention_mask'] = self.crop_attention_mask_for_cache(model_kwargs['attention_mask'], num_tokens_for_img)
del cache
torch.cuda.empty_cache()
gc.collect()
return z