Support flux 2 klein kv cache model: Use the FluxKVCache node. (#12905)

comfy/ldm/flux/model.py

@@ -44,6 +44,22 @@ class FluxParams:
     txt_norm: bool = False
 
 
+def invert_slices(slices, length):
+    sorted_slices = sorted(slices)
+    result = []
+    current = 0
+
+    for start, end in sorted_slices:
+        if current < start:
+            result.append((current, start))
+        current = max(current, end)
+
+    if current < length:
+        result.append((current, length))
+
+    return result
+
+
 class Flux(nn.Module):
     """
     Transformer model for flow matching on sequences.
@@ -138,6 +154,7 @@ class Flux(nn.Module):
         y: Tensor,
         guidance: Tensor = None,
         control = None,
+        timestep_zero_index=None,
         transformer_options={},
         attn_mask: Tensor = None,
     ) -> Tensor:
@@ -164,10 +181,6 @@ class Flux(nn.Module):
             txt = self.txt_norm(txt)
         txt = self.txt_in(txt)
 
-        vec_orig = vec
-        if self.params.global_modulation:
-            vec = (self.double_stream_modulation_img(vec_orig), self.double_stream_modulation_txt(vec_orig))
-
         if "post_input" in patches:
             for p in patches["post_input"]:
                 out = p({"img": img, "txt": txt, "img_ids": img_ids, "txt_ids": txt_ids, "transformer_options": transformer_options})
@@ -182,6 +195,24 @@ class Flux(nn.Module):
         else:
             pe = None
 
+        vec_orig = vec
+        txt_vec = vec
+        extra_kwargs = {}
+        if timestep_zero_index is not None:
+            modulation_dims = []
+            batch = vec.shape[0] // 2
+            vec_orig = vec_orig.reshape(2, batch, vec.shape[1]).movedim(0, 1)
+            invert = invert_slices(timestep_zero_index, img.shape[1])
+            for s in invert:
+                modulation_dims.append((s[0], s[1], 0))
+            for s in timestep_zero_index:
+                modulation_dims.append((s[0], s[1], 1))
+            extra_kwargs["modulation_dims_img"] = modulation_dims
+            txt_vec = vec[:batch]
+
+        if self.params.global_modulation:
+            vec = (self.double_stream_modulation_img(vec_orig), self.double_stream_modulation_txt(txt_vec))
+
         blocks_replace = patches_replace.get("dit", {})
         transformer_options["total_blocks"] = len(self.double_blocks)
         transformer_options["block_type"] = "double"
@@ -195,7 +226,8 @@ class Flux(nn.Module):
                                                    vec=args["vec"],
                                                    pe=args["pe"],
                                                    attn_mask=args.get("attn_mask"),
-                                                   transformer_options=args.get("transformer_options"))
+                                                   transformer_options=args.get("transformer_options"),
+                                                   **extra_kwargs)
                     return out
 
                 out = blocks_replace[("double_block", i)]({"img": img,
@@ -213,7 +245,8 @@ class Flux(nn.Module):
                                  vec=vec,
                                  pe=pe,
                                  attn_mask=attn_mask,
-                                 transformer_options=transformer_options)
+                                 transformer_options=transformer_options,
+                                 **extra_kwargs)
 
             if control is not None: # Controlnet
                 control_i = control.get("input")
@@ -230,6 +263,12 @@ class Flux(nn.Module):
         if self.params.global_modulation:
             vec, _ = self.single_stream_modulation(vec_orig)
 
+        extra_kwargs = {}
+        if timestep_zero_index is not None:
+            lambda a: 0 if a == 0 else a + txt.shape[1]
+            modulation_dims_combined = list(map(lambda x: (0 if x[0] == 0 else x[0] + txt.shape[1], x[1] + txt.shape[1], x[2]), modulation_dims))
+            extra_kwargs["modulation_dims"] = modulation_dims_combined
+
         transformer_options["total_blocks"] = len(self.single_blocks)
         transformer_options["block_type"] = "single"
         transformer_options["img_slice"] = [txt.shape[1], img.shape[1]]
@@ -242,7 +281,8 @@ class Flux(nn.Module):
                                        vec=args["vec"],
                                        pe=args["pe"],
                                        attn_mask=args.get("attn_mask"),
-                                       transformer_options=args.get("transformer_options"))
+                                       transformer_options=args.get("transformer_options"),
+                                       **extra_kwargs)
                     return out
 
                 out = blocks_replace[("single_block", i)]({"img": img,
@@ -253,7 +293,7 @@ class Flux(nn.Module):
                                                           {"original_block": block_wrap})
                 img = out["img"]
             else:
-                img = block(img, vec=vec, pe=pe, attn_mask=attn_mask, transformer_options=transformer_options)
+                img = block(img, vec=vec, pe=pe, attn_mask=attn_mask, transformer_options=transformer_options, **extra_kwargs)
 
             if control is not None: # Controlnet
                 control_o = control.get("output")
@@ -264,7 +304,11 @@ class Flux(nn.Module):
 
         img = img[:, txt.shape[1] :, ...]
 
-        img = self.final_layer(img, vec_orig)  # (N, T, patch_size ** 2 * out_channels)
+        extra_kwargs = {}
+        if timestep_zero_index is not None:
+            extra_kwargs["modulation_dims"] = modulation_dims
+
+        img = self.final_layer(img, vec_orig, **extra_kwargs)  # (N, T, patch_size ** 2 * out_channels)
         return img
 
     def process_img(self, x, index=0, h_offset=0, w_offset=0, transformer_options={}):
@@ -312,13 +356,16 @@ class Flux(nn.Module):
         w_len = ((w_orig + (patch_size // 2)) // patch_size)
         img, img_ids = self.process_img(x, transformer_options=transformer_options)
         img_tokens = img.shape[1]
+        timestep_zero_index = None
         if ref_latents is not None:
+            ref_num_tokens = []
             h = 0
             w = 0
             index = 0
             ref_latents_method = kwargs.get("ref_latents_method", self.params.default_ref_method)
+            timestep_zero = ref_latents_method == "index_timestep_zero"
             for ref in ref_latents:
-                if ref_latents_method == "index":
+                if ref_latents_method in ("index", "index_timestep_zero"):
                     index += self.params.ref_index_scale
                     h_offset = 0
                     w_offset = 0
@@ -342,6 +389,13 @@ class Flux(nn.Module):
                 kontext, kontext_ids = self.process_img(ref, index=index, h_offset=h_offset, w_offset=w_offset)
                 img = torch.cat([img, kontext], dim=1)
                 img_ids = torch.cat([img_ids, kontext_ids], dim=1)
+                ref_num_tokens.append(kontext.shape[1])
+            if timestep_zero:
+                if index > 0:
+                    timestep = torch.cat([timestep, timestep * 0], dim=0)
+                    timestep_zero_index = [[img_tokens, img_ids.shape[1]]]
+            transformer_options = transformer_options.copy()
+            transformer_options["reference_image_num_tokens"] = ref_num_tokens
 
         txt_ids = torch.zeros((bs, context.shape[1], len(self.params.axes_dim)), device=x.device, dtype=torch.float32)
 
@@ -349,6 +403,6 @@ class Flux(nn.Module):
             for i in self.params.txt_ids_dims:
                 txt_ids[:, :, i] = torch.linspace(0, context.shape[1] - 1, steps=context.shape[1], device=x.device, dtype=torch.float32)
 
-        out = self.forward_orig(img, img_ids, context, txt_ids, timestep, y, guidance, control, transformer_options, attn_mask=kwargs.get("attention_mask", None))
+        out = self.forward_orig(img, img_ids, context, txt_ids, timestep, y, guidance, control, timestep_zero_index=timestep_zero_index, transformer_options=transformer_options, attn_mask=kwargs.get("attention_mask", None))
         out = out[:, :img_tokens]
         return rearrange(out, "b (h w) (c ph pw) -> b c (h ph) (w pw)", h=h_len, w=w_len, ph=self.patch_size, pw=self.patch_size)[:,:,:h_orig,:w_orig]

comfy_extras/nodes_flux.py

@@ -6,6 +6,7 @@ import comfy.model_management
 import torch
 import math
 import nodes
+import comfy.ldm.flux.math
 
 class CLIPTextEncodeFlux(io.ComfyNode):
     @classmethod
@@ -231,6 +232,68 @@ class Flux2Scheduler(io.ComfyNode):
         sigmas = get_schedule(steps, round(seq_len))
         return io.NodeOutput(sigmas)
 
+class KV_Attn_Input:
+    def __init__(self):
+        self.cache = {}
+
+    def __call__(self, q, k, v, extra_options, **kwargs):
+        reference_image_num_tokens = extra_options.get("reference_image_num_tokens", [])
+        if len(reference_image_num_tokens) == 0:
+            return {}
+
+        ref_toks = sum(reference_image_num_tokens)
+        cache_key = "{}_{}".format(extra_options["block_type"], extra_options["block_index"])
+        if cache_key in self.cache:
+            kk, vv = self.cache[cache_key]
+            self.set_cache = False
+            return {"q": q, "k": torch.cat((k, kk), dim=2), "v": torch.cat((v, vv), dim=2)}
+
+        self.cache[cache_key] = (k[:, :, -ref_toks:], v[:, :, -ref_toks:])
+        self.set_cache = True
+        return {"q": q, "k": k, "v": v}
+
+    def cleanup(self):
+        self.cache = {}
+
+
+class FluxKVCache(io.ComfyNode):
+    @classmethod
+    def define_schema(cls) -> io.Schema:
+        return io.Schema(
+            node_id="FluxKVCache",
+            display_name="Flux KV Cache",
+            description="Enables KV Cache optimization for reference images on Flux family models.",
+            category="",
+            is_experimental=True,
+            inputs=[
+                io.Model.Input("model", tooltip="The model to use KV Cache on."),
+            ],
+            outputs=[
+                io.Model.Output(tooltip="The patched model with KV Cache enabled."),
+            ],
+        )
+
+    @classmethod
+    def execute(cls, model: io.Model.Type) -> io.NodeOutput:
+        m = model.clone()
+        input_patch_obj = KV_Attn_Input()
+
+        def model_input_patch(inputs):
+            if len(input_patch_obj.cache) > 0:
+                ref_image_tokens = sum(inputs["transformer_options"].get("reference_image_num_tokens", []))
+                if ref_image_tokens > 0:
+                    img = inputs["img"]
+                    inputs["img"] = img[:, :-ref_image_tokens]
+            return inputs
+
+        m.set_model_attn1_patch(input_patch_obj)
+        m.set_model_post_input_patch(model_input_patch)
+        if hasattr(model.model.diffusion_model, "params"):
+            m.add_object_patch("diffusion_model.params.default_ref_method", "index_timestep_zero")
+        else:
+            m.add_object_patch("diffusion_model.default_ref_method", "index_timestep_zero")
+
+        return io.NodeOutput(m)
 
 class FluxExtension(ComfyExtension):
     @override
@@ -243,6 +306,7 @@ class FluxExtension(ComfyExtension):
             FluxKontextMultiReferenceLatentMethod,
             EmptyFlux2LatentImage,
             Flux2Scheduler,
+            FluxKVCache,
         ]