⚡️ Speed up method AutoencoderKLWan.clear_cache by 886%

src/diffusers/models/autoencoders/autoencoder_kl_wan.py

@@ -749,6 +749,12 @@ def __init__(
         self.tile_sample_stride_height = 192
         self.tile_sample_stride_width = 192
 
+        # Precompute and cache conv counts for encoder and decoder for clear_cache speedup
+        self._cached_conv_counts = {
+            "decoder": self._count_conv3d_fast(self.decoder),
+            "encoder": self._count_conv3d_fast(self.encoder),
+        }
+
     def enable_tiling(
         self,
         tile_sample_min_height: Optional[int] = None,
@@ -801,18 +807,12 @@ def disable_slicing(self) -> None:
         self.use_slicing = False
 
     def clear_cache(self):
-        def _count_conv3d(model):
-            count = 0
-            for m in model.modules():
-                if isinstance(m, WanCausalConv3d):
-                    count += 1
-            return count
-
-        self._conv_num = _count_conv3d(self.decoder)
+        # Use cached conv counts for decoder and encoder to avoid re-iterating modules each call
+        self._conv_num = self._cached_conv_counts["decoder"]
         self._conv_idx = [0]
         self._feat_map = [None] * self._conv_num
         # cache encode
-        self._enc_conv_num = _count_conv3d(self.encoder)
+        self._enc_conv_num = self._cached_conv_counts["encoder"]
         self._enc_conv_idx = [0]
         self._enc_feat_map = [None] * self._enc_conv_num
 
@@ -1083,3 +1083,8 @@ def forward(
             z = posterior.mode()
         dec = self.decode(z, return_dict=return_dict)
         return dec
+
+    @staticmethod
+    def _count_conv3d_fast(model):
+        # Fast version: relies on model.modules() being a generator; avoids Python loop overhead by using sum + generator expression
+        return sum(isinstance(m, WanCausalConv3d) for m in model.modules())