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import torch |
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import intel_extension_for_pytorch as ipex |
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import diffusers |
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from diffusers.models.attention_processor import Attention |
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class SlicedAttnProcessor: |
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r""" |
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Processor for implementing sliced attention. |
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Args: |
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slice_size (`int`, *optional*): |
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The number of steps to compute attention. Uses as many slices as `attention_head_dim // slice_size`, and |
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`attention_head_dim` must be a multiple of the `slice_size`. |
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""" |
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def __init__(self, slice_size): |
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self.slice_size = slice_size |
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def __call__(self, attn: Attention, hidden_states, encoder_hidden_states=None, attention_mask=None): |
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residual = hidden_states |
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input_ndim = hidden_states.ndim |
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if input_ndim == 4: |
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batch_size, channel, height, width = hidden_states.shape |
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hidden_states = hidden_states.view(batch_size, channel, height * width).transpose(1, 2) |
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batch_size, sequence_length, _ = ( |
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hidden_states.shape if encoder_hidden_states is None else encoder_hidden_states.shape |
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) |
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attention_mask = attn.prepare_attention_mask(attention_mask, sequence_length, batch_size) |
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if attn.group_norm is not None: |
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hidden_states = attn.group_norm(hidden_states.transpose(1, 2)).transpose(1, 2) |
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query = attn.to_q(hidden_states) |
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dim = query.shape[-1] |
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query = attn.head_to_batch_dim(query) |
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if encoder_hidden_states is None: |
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encoder_hidden_states = hidden_states |
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elif attn.norm_cross: |
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encoder_hidden_states = attn.norm_encoder_hidden_states(encoder_hidden_states) |
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key = attn.to_k(encoder_hidden_states) |
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value = attn.to_v(encoder_hidden_states) |
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key = attn.head_to_batch_dim(key) |
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value = attn.head_to_batch_dim(value) |
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batch_size_attention, query_tokens, shape_three = query.shape |
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hidden_states = torch.zeros( |
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(batch_size_attention, query_tokens, dim // attn.heads), device=query.device, dtype=query.dtype |
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) |
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block_multiply = query.element_size() |
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slice_block_size = self.slice_size * shape_three / 1024 / 1024 * block_multiply |
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block_size = query_tokens * slice_block_size |
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split_2_slice_size = query_tokens |
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if block_size > 4: |
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do_split_2 = True |
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while (split_2_slice_size * slice_block_size) > 4: |
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split_2_slice_size = split_2_slice_size // 2 |
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if split_2_slice_size <= 1: |
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split_2_slice_size = 1 |
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break |
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else: |
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do_split_2 = False |
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for i in range(batch_size_attention // self.slice_size): |
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start_idx = i * self.slice_size |
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end_idx = (i + 1) * self.slice_size |
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if do_split_2: |
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for i2 in range(query_tokens // split_2_slice_size): |
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start_idx_2 = i2 * split_2_slice_size |
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end_idx_2 = (i2 + 1) * split_2_slice_size |
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query_slice = query[start_idx:end_idx, start_idx_2:end_idx_2] |
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key_slice = key[start_idx:end_idx, start_idx_2:end_idx_2] |
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attn_mask_slice = attention_mask[start_idx:end_idx, start_idx_2:end_idx_2] if attention_mask is not None else None |
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attn_slice = attn.get_attention_scores(query_slice, key_slice, attn_mask_slice) |
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attn_slice = torch.bmm(attn_slice, value[start_idx:end_idx, start_idx_2:end_idx_2]) |
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hidden_states[start_idx:end_idx, start_idx_2:end_idx_2] = attn_slice |
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else: |
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query_slice = query[start_idx:end_idx] |
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key_slice = key[start_idx:end_idx] |
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attn_mask_slice = attention_mask[start_idx:end_idx] if attention_mask is not None else None |
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attn_slice = attn.get_attention_scores(query_slice, key_slice, attn_mask_slice) |
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attn_slice = torch.bmm(attn_slice, value[start_idx:end_idx]) |
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hidden_states[start_idx:end_idx] = attn_slice |
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hidden_states = attn.batch_to_head_dim(hidden_states) |
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hidden_states = attn.to_out[0](hidden_states) |
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hidden_states = attn.to_out[1](hidden_states) |
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if input_ndim == 4: |
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hidden_states = hidden_states.transpose(-1, -2).reshape(batch_size, channel, height, width) |
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if attn.residual_connection: |
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hidden_states = hidden_states + residual |
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hidden_states = hidden_states / attn.rescale_output_factor |
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return hidden_states |
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def ipex_diffusers(): |
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diffusers.models.attention_processor.SlicedAttnProcessor = SlicedAttnProcessor |
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