precache fa3 kernel and font before gpu task

app.py

@@ -88,10 +88,11 @@ _preloaded_embedding = None
 _preloaded_tokenizer = None
 _cached_t5_dir = None
 _cached_clip_dir = None
+_cached_font_path = None
 
 def preload_model_files():
     """Pre-download model files to cache at startup (no GPU needed)"""
-    global _preloaded_embedding, _preloaded_tokenizer, _cached_t5_dir, _cached_clip_dir
+    global _preloaded_embedding, _preloaded_tokenizer, _cached_t5_dir, _cached_clip_dir, _cached_font_path
     from huggingface_hub import snapshot_download, hf_hub_download
     
     hf_token = os.environ.get("HF_TOKEN", None)
@@ -136,8 +137,28 @@ def preload_model_files():
         print("✓ VAE cached")
     except Exception as e:
         print(f"Warning: Could not pre-download VAE: {e}")
+
+    # 5. Font file used for condition image rendering
+    try:
+        _cached_font_path = hf_hub_download(
+            repo_id="TSXu/Unicalli_Pro",
+            filename="FangZhengKaiTiFanTi-1.ttf",
+            token=hf_token,
+        )
+        os.environ["UNICALLI_FONT_PATH"] = _cached_font_path
+        print(f"✓ Font cached at: {_cached_font_path}")
+    except Exception as e:
+        print(f"Warning: Could not pre-download font: {e}")
+
+    # 6. Flash Attention 3 kernel package (large) pre-cache
+    try:
+        from kernels import get_kernel
+        get_kernel("kernels-community/vllm-flash-attn3")
+        print("✓ Flash Attention 3 kernel cached")
+    except Exception as e:
+        print(f"Warning: Could not pre-cache Flash Attention 3 kernel: {e}")
     
-    # 5. Pre-load InternVL embedding to CPU memory (saves ~5s in GPU session)
+    # 7. Pre-load InternVL embedding to CPU memory (saves ~5s in GPU session)
     if local_dir:
         try:
             intern_vlm_path = os.path.join(local_dir, "internvl_embedding")

inference.py

@@ -303,6 +303,10 @@ class CalligraphyGenerator:
         Returns:
             Path to the local font file
         """
+        cached_font_path = os.environ.get("UNICALLI_FONT_PATH")
+        if cached_font_path and os.path.exists(cached_font_path):
+            return cached_font_path
+
         if os.path.exists(font_path):
             return font_path