vae decode dp for wan

Author: TmacAaron

src/diffusers/models/autoencoders/autoencoder_kl_wan.py

@@ -17,6 +17,7 @@
 import torch
 import torch.nn as nn
 import torch.nn.functional as F
+import torch.distributed as dist
 
 from ...configuration_utils import ConfigMixin, register_to_config
 from ...loaders import FromOriginalModelMixin
@@ -1073,6 +1074,8 @@ def __init__(
         self.tile_sample_stride_height = 192
         self.tile_sample_stride_width = 192
 
+        self.use_dp = False
+
         # Precompute and cache conv counts for encoder and decoder for clear_cache speedup
         self._cached_conv_counts = {
             "decoder": sum(isinstance(m, WanCausalConv3d) for m in self.decoder.modules())
@@ -1113,6 +1116,53 @@ def enable_tiling(
         self.tile_sample_stride_height = tile_sample_stride_height or self.tile_sample_stride_height
         self.tile_sample_stride_width = tile_sample_stride_width or self.tile_sample_stride_width
 
+    def enable_dp(
+        self,
+        world_size: Optional[int] = None,
+        hw_splits: Optional[Tuple[int, int]] = None,
+        overlap_ratio: Optional[float] = None,
+        overlap_pixels: Optional[int] = None
+    ) -> None:
+        r"""
+        """
+        if world_size is None:
+            world_size = dist.get_world_size()
+
+        if world_size <= 1 or world_size > dist.get_world_size():
+            return
+
+        if hw_splits is None:
+            hw_splits = (1, int(world_size))
+
+        assert len(hw_splits) == 2, f"'hw_splits' should be a tuple of 2 int, but got length {len(hw_splits)}"
+
+        h_split, w_split = map(int, hw_splits)
+        num_tiles = h_split * w_split
+
+        # assert h_split * w_split == world_size, \
+        #     (f"world_size must be {w_split} * {h_split} = {w_split * h_split}, but got {world_size}")
+
+        self.use_dp = True
+        self.h_split, self.w_split = h_split, w_split
+        self.world_size = world_size
+        self.overlap_ratio = overlap_ratio
+        self.overlap_pixels = overlap_pixels
+
+        dp_ranks = list(range(0, world_size))
+        self.vae_dp_group = dist.new_group(ranks=dp_ranks)
+        self.rank = dist.get_rank()
+        # patch_ranks_flatten = [tile_idx % world_size for tile_idx in range(num_tiles)]
+        # self.patch_ranks = torch.Tensor(patch_ranks_flatten).reshape(h_split, w_split)
+        self.tile_idxs_per_rank = [[] for _ in range(self.world_size)]
+        self.num_tiles_per_rank = [0] * self.world_size
+        rank_idx = 0
+        for h_idx in range(self.h_split):
+            for w_idx in range(self.w_split):
+                rank_idx %= self.world_size
+                self.tile_idxs_per_rank[rank_idx].append((h_idx, w_idx))
+                self.num_tiles_per_rank[rank_idx] += 1
+                rank_idx += 1
+
     def clear_cache(self):
         # Use cached conv counts for decoder and encoder to avoid re-iterating modules each call
         self._conv_num = self._cached_conv_counts["decoder"]
@@ -1182,6 +1232,9 @@ def _decode(self, z: torch.Tensor, return_dict: bool = True):
         tile_latent_min_height = self.tile_sample_min_height // self.spatial_compression_ratio
         tile_latent_min_width = self.tile_sample_min_width // self.spatial_compression_ratio
 
+        if self.use_dp:
+            return self.tiled_decode_with_dp(z, return_dict=return_dict)
+
         if self.use_tiling and (width > tile_latent_min_width or height > tile_latent_min_height):
             return self.tiled_decode(z, return_dict=return_dict)
 
@@ -1393,6 +1446,152 @@ def tiled_decode(self, z: torch.Tensor, return_dict: bool = True) -> Union[Decod
             return (dec,)
         return DecoderOutput(sample=dec)
 
+    def tiled_decode_with_dp(self, z: torch.Tensor, return_dict: bool = True) -> Union[DecoderOutput, torch.Tensor]:
+        r"""
+        Decode a batch of images using a tiled decoder.
+
+        Args:
+            z (`torch.Tensor`): Input batch of latent vectors.
+            return_dict (`bool`, *optional*, defaults to `True`):
+                Whether or not to return a [`~models.vae.DecoderOutput`] instead of a plain tuple.
+
+        Returns:
+            [`~models.vae.DecoderOutput`] or `tuple`:
+                If return_dict is True, a [`~models.vae.DecoderOutput`] is returned, otherwise a plain `tuple` is
+                returned.
+        """
+        _, _, num_frames, height, width = z.shape
+        device = z.device
+        sample_height = height * self.spatial_compression_ratio
+        sample_width = width * self.spatial_compression_ratio
+
+        # Calculate stride based on h_split and w_split
+        tile_latent_stride_height = int((height + self.h_split - 1) / self.h_split)
+        tile_latent_stride_width = int((width + self.w_split - 1) / self.w_split)
+
+        # Calculate overlap in latent space
+        overlap_latent_height = 3
+        overlap_latent_width = 3
+        if self.overlap_pixels is not None:
+            overlap_latent = (self.overlap_pixels + self.spatial_compression_ratio - 1) // self.spatial_compression_ratio
+            overlap_latent_height = overlap_latent
+            overlap_latent_width = overlap_latent
+        elif self.overlap_ratio is not None:
+            overlap_latent_height = int(self.overlap_ratio * height)
+            overlap_latent_width = int(self.overlap_ratio * width)
+
+        # Calculate minimum tile size in latent space
+        tile_latent_min_height = tile_latent_stride_height + overlap_latent_height
+        tile_latent_min_width = tile_latent_stride_width + overlap_latent_width
+
+        # Convert min/stride to sample space
+        tile_sample_min_height = tile_latent_min_height * self.spatial_compression_ratio
+        tile_sample_min_width = tile_latent_min_width * self.spatial_compression_ratio
+        tile_sample_stride_height = tile_latent_stride_height * self.spatial_compression_ratio
+        tile_sample_stride_width = tile_latent_stride_width * self.spatial_compression_ratio
+
+        self.tile_sample_min_height = tile_sample_min_height
+        self.tile_sample_min_width = tile_sample_min_width
+        self.tile_sample_stride_height = tile_sample_stride_height
+        self.tile_sample_stride_width = tile_sample_stride_width
+
+        if self.config.patch_size is not None:
+            sample_height = sample_height // self.config.patch_size
+            sample_width = sample_width // self.config.patch_size
+            tile_sample_stride_height = tile_sample_stride_height // self.config.patch_size
+            tile_sample_stride_width = tile_sample_stride_width // self.config.patch_size
+            blend_height = self.tile_sample_min_height // self.config.patch_size - tile_sample_stride_height
+            blend_width = self.tile_sample_min_width // self.config.patch_size - tile_sample_stride_width
+        else:
+            blend_height = self.tile_sample_min_height - tile_sample_stride_height
+            blend_width = self.tile_sample_min_width - tile_sample_stride_width
+
+        # Split z into overlapping tiles and decode them separately.
+        # The tiles have an overlap to avoid seams between tiles.
+        # Determine tile grid dimensions - patch_ranks shape is [h_split, w_split]
+        num_tile_rows = self.h_split
+        num_tile_cols = self.w_split
+
+        # Each rank computes only tiles assigned to it based on tile_idxs_per_rank
+        # local_tiles = []  # List to store tiles computed by this rank
+        local_tiles = []
+        local_hw_shapes = []
+        
+        for h_idx, w_idx in self.tile_idxs_per_rank[self.rank]:
+            self.clear_cache()
+            patch_height_start = h_idx * tile_latent_stride_height
+            patch_height_end = patch_height_start + tile_latent_min_height
+            patch_width_start = w_idx * tile_latent_stride_width
+            patch_width_end = patch_width_start + tile_latent_min_width
+            time = []
+            for k in range(num_frames):
+                self._conv_idx = [0]
+                tile = z[:, :, k : k + 1, patch_height_start : patch_height_end, patch_width_start : patch_width_end]
+                tile = self.post_quant_conv(tile)
+                decoded = self.decoder(
+                    tile, feat_cache=self._feat_map, feat_idx=self._conv_idx, first_chunk=(k == 0)
+                )
+                time.append(decoded)
+            time = torch.cat(time, dim=2)
+            local_tiles.append(time.flatten(3, 4)) # flatten h,w dim for concate all tiles in one rank
+            local_hw_shapes.append(torch.Tensor([*time.shape[3:5]]).to(device).int()) # record hw for futher unflatten
+            self.clear_cache()
+
+        # concat all tiles on local rank
+        local_tiles = torch.cat(local_tiles, dim=3)
+        local_hw_shapes = torch.stack(local_hw_shapes)
+
+        # get all hw shapes for each rank (perhaps has different shapes for last tile)
+        gathered_shape_list = [torch.empty((num_tiles, 2), dtype=local_hw_shapes.dtype, device=device) 
+                        for num_tiles in self.num_tiles_per_rank]
+        dist.all_gather(gathered_shape_list, local_hw_shapes, group=self.vae_dp_group)
+
+        # gather tiles on all ranks
+        b, c, n = local_tiles.shape[:3]
+        gathered_tiles = [
+            torch.empty(
+                (b, c, n, tiles_shape.prod(dim=1).sum().item()), 
+                dtype=local_tiles.dtype, device=device) for tiles_shape in gathered_shape_list
+        ]
+        dist.all_gather(gathered_tiles, local_tiles, group=self.vae_dp_group)
+
+        # put tiles in rows based on tile_idxs_per_rank
+        rows = [[None] * num_tile_cols for _ in range(num_tile_rows)]
+        for rank_idx, tile_idxs in enumerate(self.tile_idxs_per_rank):
+            rank_tile_hw_shapes = gathered_shape_list[rank_idx]
+            hw_start_idx = 0
+            # perhaps has more than one tile in each rank, get each by hw_shapes
+            for tile_idx, (h_idx, w_idx) in enumerate(tile_idxs):
+                rank_tile_hw_shape = rank_tile_hw_shapes[tile_idx]
+                hw_end_idx = hw_start_idx + rank_tile_hw_shape.prod().item() # flattend hw
+                rows[h_idx][w_idx] = gathered_tiles[rank_idx][:, :, :, hw_start_idx:hw_end_idx].unflatten(
+                    3, rank_tile_hw_shape.tolist()) # unflatten hw dim
+                hw_start_idx = hw_end_idx
+
+        # combine all tiles, same as tiled decode
+        result_rows = []
+        for i, row in enumerate(rows):
+            result_row = []
+            for j, tile in enumerate(row):
+                # blend the above tile and the left tile
+                # to the current tile and add the current tile to the result row
+                if i > 0:
+                    tile = self.blend_v(rows[i - 1][j], tile, blend_height)
+                if j > 0:
+                    tile = self.blend_h(row[j - 1], tile, blend_width)
+                result_row.append(tile[:, :, :, :tile_sample_stride_height, :tile_sample_stride_width])
+            result_rows.append(torch.cat(result_row, dim=-1))
+        dec = torch.cat(result_rows, dim=3)[:, :, :, :sample_height, :sample_width]
+
+        if self.config.patch_size is not None:
+            dec = unpatchify(dec, patch_size=self.config.patch_size)
+
+        dec = torch.clamp(dec, min=-1.0, max=1.0)
+
+        if not return_dict:
+            return (dec,)
+        return DecoderOutput(sample=dec)
+
     def forward(
         self,
         sample: torch.Tensor,