[feat] Added Quest Sparsity Policy.

nanovllm/config.py

@@ -1,9 +1,16 @@
 import os
 from dataclasses import dataclass
+from enum import Enum, auto
 from transformers import AutoConfig
 import torch
 
 
+class SparsePolicyType(Enum):
+    """Sparse attention policy types."""
+    FULL = auto()   # No sparse attention (load all blocks)
+    QUEST = auto()  # Query-aware Top-K block selection (decode only)
+
+
 @dataclass
 class Config:
     model: str
@@ -29,11 +36,10 @@ class Config:
     num_gpu_kvcache_blocks: int = -1
     num_cpu_kvcache_blocks: int = -1
 
-    # Sparse attention configuration (dual policy architecture)
-    prefill_policy: str = "full"  # "full", "quest", "vertical_slash", "streaming_llm"
-    decode_policy: str = "full"   # "full", "quest", "vertical_slash", "streaming_llm"
-    sparse_num_sink_blocks: int = 1  # Number of sink blocks for sparse patterns
-    sparse_local_window_blocks: int = 2  # Local window size for VerticalSlash
+    # Sparse attention configuration
+    # Quest: decode-only sparse attention with Top-K block selection
+    # FULL: no sparse attention (load all blocks)
+    sparse_policy: SparsePolicyType = SparsePolicyType.FULL
     sparse_topk_blocks: int = 8  # Top-K blocks for Quest
     sparse_threshold_blocks: int = 4  # Apply sparse only when blocks > threshold