vram optimization

diffsynth/models/wan_video_dit.py

@@ -291,17 +291,21 @@ class WanModel(torch.nn.Module):
                 clip_feature: Optional[torch.Tensor] = None,
                 y: Optional[torch.Tensor] = None,
                 use_gradient_checkpointing: bool = False,
+                use_gradient_checkpointing_offload: bool = False,
                 **kwargs,
                 ):
         t = self.time_embedding(
             sinusoidal_embedding_1d(self.freq_dim, timestep))
         t_mod = self.time_projection(t).unflatten(1, (6, self.dim))
         context = self.text_embedding(context)
+        
         if self.has_image_input:
             x = torch.cat([x, y], dim=1)  # (b, c_x + c_y, f, h, w)
             clip_embdding = self.img_emb(clip_feature)
             context = torch.cat([clip_embdding, context], dim=1)
+        
         x, (f, h, w) = self.patchify(x)
+        
         freqs = torch.cat([
             self.freqs[0][:f].view(f, 1, 1, -1).expand(f, h, w, -1),
             self.freqs[1][:h].view(1, h, 1, -1).expand(f, h, w, -1),
@@ -315,11 +319,19 @@ class WanModel(torch.nn.Module):
 
         for block in self.blocks:
             if self.training and use_gradient_checkpointing:
-                x = torch.utils.checkpoint.checkpoint(
-                    create_custom_forward(block),
-                    x, context, t_mod, freqs,
-                    use_reentrant=False,
-                )
+                if use_gradient_checkpointing_offload:
+                    with torch.autograd.graph.save_on_cpu():
+                        x = torch.utils.checkpoint.checkpoint(
+                            create_custom_forward(block),
+                            x, context, t_mod, freqs,
+                            use_reentrant=False,
+                        )
+                else:
+                    x = torch.utils.checkpoint.checkpoint(
+                        create_custom_forward(block),
+                        x, context, t_mod, freqs,
+                        use_reentrant=False,
+                    )
             else:
                 x = block(x, context, t_mod, freqs)
 

diffsynth/models/wan_video_image_encoder.py

@@ -228,7 +228,7 @@ class QuickGELU(nn.Module):
 class LayerNorm(nn.LayerNorm):
 
     def forward(self, x):
-        return super().forward(x.float()).type_as(x)
+        return super().forward(x).type_as(x)
 
 
 class SelfAttention(nn.Module):
@@ -256,15 +256,11 @@ class SelfAttention(nn.Module):
         """
         x:   [B, L, C].
         """
-        b, s, c, n, d = *x.size(), self.num_heads, self.head_dim
-
         # compute query, key, value
-        q, k, v = self.to_qkv(x).view(b, s, 3, n, d).unbind(2)
+        q, k, v = self.to_qkv(x).chunk(3, dim=-1)
 
         # compute attention
-        p = self.attn_dropout if self.training else 0.0
-        x = flash_attention(q, k, v, dropout_p=p, causal=self.causal, version=2)
-        x = x.reshape(b, s, c)
+        x = flash_attention(q, k, v, num_heads=self.num_heads)
 
         # output
         x = self.proj(x)
@@ -371,11 +367,11 @@ class AttentionPool(nn.Module):
         b, s, c, n, d = *x.size(), self.num_heads, self.head_dim
 
         # compute query, key, value
-        q = self.to_q(self.cls_embedding).view(1, 1, n, d).expand(b, -1, -1, -1)
-        k, v = self.to_kv(x).view(b, s, 2, n, d).unbind(2)
+        q = self.to_q(self.cls_embedding).view(1, 1, n*d).expand(b, -1, -1)
+        k, v = self.to_kv(x).chunk(2, dim=-1)
 
         # compute attention
-        x = flash_attention(q, k, v, version=2)
+        x = flash_attention(q, k, v, num_heads=self.num_heads)
         x = x.reshape(b, 1, c)
 
         # output
@@ -878,6 +874,8 @@ class WanImageEncoder(torch.nn.Module):
         videos = self.transforms.transforms[-1](videos.mul_(0.5).add_(0.5))
 
         # forward
+        dtype = next(iter(self.model.visual.parameters())).dtype
+        videos = videos.to(dtype)
         out = self.model.visual(videos, use_31_block=True)
         return out
         

diffsynth/models/wan_video_vae.py

@@ -688,7 +688,7 @@ class WanVideoVAE(nn.Module):
                 target_w: target_w + hidden_states_batch.shape[4],
             ] += mask
         values = values / weight
-        values = values.float().clamp_(-1, 1)
+        values = values.clamp_(-1, 1)
         return values
 
 
@@ -740,20 +740,19 @@ class WanVideoVAE(nn.Module):
                 target_w: target_w + hidden_states_batch.shape[4],
             ] += mask
         values = values / weight
-        values = values.float()
         return values
 
 
     def single_encode(self, video, device):
         video = video.to(device)
         x = self.model.encode(video, self.scale)
-        return x.float()
+        return x
 
 
     def single_decode(self, hidden_state, device):
         hidden_state = hidden_state.to(device)
         video = self.model.decode(hidden_state, self.scale)
-        return video.float().clamp_(-1, 1)
+        return video.clamp_(-1, 1)
 
 
     def encode(self, videos, device, tiled=False, tile_size=(34, 34), tile_stride=(18, 16)):