[optimizer] unify linear attention and TTL on one LiteHit core and retire the legacy indexer

kv_cache_manager/optimizer/docs/optimizer_architecture.md

@@ -43,7 +43,7 @@ KVCacheManager Optimizer is a standalone cache optimization analysis module. It
 The Optimizer currently contains two execution paths: offline trace replay and online optimization service:
 
 - The offline replay path uses `OptimizerManager`, `OptIndexerManager`, `OptEvictionManager`, and `RadixTreeIndex`, depending on replay configuration, trace loader/converter, and data storage types.
-- The online service path uses `OnlineOptimizerManager`, LiteHit, `CacheIndexerFactory`, `LruCacheIndexer`/`TtlCacheIndexerWrapper`, and service/protobuf interfaces, depending on online instance group/instance configuration and registry. Full-attention multi-capacity LRU is directly held by `InstanceState` as LiteHit; linear attention is still simulated by the generic `CacheIndexer`.
+- The online service path uses `OnlineOptimizerManager`, the unified LiteHit runtime, and service/protobuf interfaces, depending on online instance group/instance configuration and registry. Each `InstanceState` holds one `TtlLiteHit` decorator with a single `LiteHit` core inside; full attention uses the Full-only policy, and linear attention additionally enables the Linear state policy.
 
 The two paths share the hit-rate modeling code within the optimizer module, but the runtime, configuration targets, and service boundaries remain independent, avoiding the online service introducing offline replay/data storage dependencies.
 
@@ -78,9 +78,10 @@ OnlineOptimizerManager (online runtime coordinator)
     ├── OptimizerRegistryManager (instance group/instance persistence)
     └── InstanceState (instance_id-isolated runtime state)
         ↓
-    ├── LiteHit (full-attention multi-capacity LRU)
-    └── CacheIndexerFactory (linear attention)
-        └── LruCacheIndexer / TtlCacheIndexerWrapper
+    └── LiteHit (unified weighted LRU core)
+        ├── Full-only (optional block-RLE)
+        └── Linear state policy (mixed Full + Linear charges)
+                    both can layer a fixed TTL
 ```
 
 ### Directory Structure
@@ -97,10 +98,12 @@ kv_cache_manager/optimizer/
 │   └── online_runtime/              # online runtime
 │       └── online_optimizer_manager.h/cc # online instance registration, TraceQuery, and statistics
 ├── index/                # index layer
-│   ├── radix_tree_index.h/cc        # offline Radix tree index
-│   └── online/                    # linear attention online capacity/TTL indexer
-├── liteHit/              # lightweight multi-capacity full-attention LRU hit-rate core
-│   ├── lite_hit.h/cc                # multi-capacity LRU hit-rate analyzer
+│   └── radix_tree_index.h/cc        # offline Radix tree index
+├── liteHit/              # lightweight multi-capacity hit-rate core
+│   ├── lite_hit.h/cc                # capacity-independent weighted LRU core shared by Full/Mamba
+│   ├── lite_hit_linear.h/cc         # Linear state restore points and write policy (no separate LRU state)
+│   ├── lite_hit_ttl.h/cc            # fixed-TTL decorator wrapping LiteHit (epochs/watermark)
+│   ├── weighted_lru_pool.h/cc       # byte-weighted LRU pool (typed keys: Full / Linear)
 │   └── dynamic_fenwick_tree.h/cc    # order-statistics Fenwick for reuse-distance
 ├── eviction_policy/      # eviction policy layer
 │   ├── base.h                   # policy base class
@@ -156,7 +159,9 @@ kv_cache_manager/optimizer/
 
 The online service protocol is defined in `kv_cache_manager/protocol/protobuf/optimizer_service.proto`, and is converted by the service layer into optimizer online config/runtime objects.
 
-A full-attention TraceQuery only puts complete blocks into `block_keys`, and passes the original input length including trailing tokens via `input_token_len`. The Online Manager uses the fixed byte charge of the full location spec group to floor `capacity_gb` to block capacity, then hands the same request to LiteHit; both per-request and cumulative hit rates are `prefix_hit_blocks * block_size_tokens / input_tokens`. When old clients lack the length, the compatibility assumption is that there are no trailing tokens. When a full-attention group config has `ttl_seconds != 0`, a fixed TTL is layered on top of LiteHit with wall-clock time (metrics consistent with `TtlCacheIndexerWrapper`); the statistics metrics and TTL behavior of linear attention keep the legacy path unchanged.
+A full-attention TraceQuery only puts complete blocks into `block_keys`, and passes the original input length including trailing tokens via `input_token_len`. Like linear attention, the Online Manager keeps only byte capacities; the core's default byte-step can be losslessly compressed into Full-only block RLE, and the fixed byte charge of the full location spec group performs a single floor only at final projection. Both per-request and cumulative hit rates are `prefix_hit_blocks * block_size_tokens / input_tokens`. When old clients lack the length, the compatibility assumption is that there are no trailing tokens.
+
+Linear attention (`linear_step > 0`) enables the Linear state policy on the same LiteHit: a Full block and a Linear state are two independent objects that share **one recency order and one total byte budget**; the capacity axis is total bytes rather than a block count, and the hit semantics is "resume from a Linear state". `LiteHit` itself has no notion of time; the outer `TtlLiteHit` decorator filters both Full and Linear states with a shared epoch/watermark, expiring an object from the weighted LRU's visible set once its age reaches the group TTL. Online uses wall-clock time, offline uses trace timestamps, and with TTL 0 the decorator is a transparent pass-through.
 
 ---
 

kv_cache_manager/optimizer/docs/optimizer_architecture_zh.md

@@ -43,7 +43,7 @@ KVCacheManager Optimizer 是一个独立的缓存优化分析模块，通过回
 Optimizer 当前包含离线 trace 回放和在线优化服务两条运行路径：
 
 - 离线回放路径使用 `OptimizerManager`、`OptIndexerManager`、`OptEvictionManager` 和 `RadixTreeIndex`，依赖 replay 配置、trace loader/converter 和 data storage 类型。
-- 在线服务路径使用 `OnlineOptimizerManager`、LiteHit、`CacheIndexerFactory`、`LruCacheIndexer`/`TtlCacheIndexerWrapper` 和 service/protobuf 接口，依赖 online 实例组/实例配置与 registry。full-attention 多容量 LRU 由 `InstanceState` 直接持有 LiteHit；linear attention 仍由通用 `CacheIndexer` 模拟。
+- 在线服务路径使用 `OnlineOptimizerManager`、统一的 LiteHit 运行时和 service/protobuf 接口，依赖 online 实例组/实例配置与 registry。每个 `InstanceState` 持有一个 `TtlLiteHit` decorator，内部只有一个 `LiteHit` core；full-attention 使用 Full-only 策略，linear attention 额外启用 Linear state 策略。
 
 两条路径共享 optimizer 模块内的命中率建模代码，但运行时、配置 target 和服务边界保持独立，避免在线服务引入离线 replay/data storage 依赖。
 
@@ -78,9 +78,10 @@ OnlineOptimizerManager (在线运行时协调器)
     ├── OptimizerRegistryManager (实例组/实例持久化)
     └── InstanceState (instance_id 隔离的运行状态)
         ↓
-    ├── LiteHit (full-attention 多容量 LRU)
-    └── CacheIndexerFactory (linear attention)
-        └── LruCacheIndexer / TtlCacheIndexerWrapper
+    └── LiteHit (统一 weighted LRU core)
+        ├── Full-only（可选 block-RLE）
+        └── Linear state policy（Full + Linear 混合 charge）
+                    两者均可叠固定 TTL
 ```
 
 ### 目录结构
@@ -97,10 +98,12 @@ kv_cache_manager/optimizer/
 │   └── online_runtime/              # 在线运行时
 │       └── online_optimizer_manager.h/cc # 在线实例注册、TraceQuery 和统计
 ├── index/                # 索引层
-│   ├── radix_tree_index.h/cc        # 离线 Radix 树索引
-│   └── online/                    # linear attention 在线容量/TTL 索引器
-├── liteHit/              # 轻量多容量 full-attention LRU 命中率核心
-│   ├── lite_hit.h/cc                # 多容量 LRU 命中率分析器
+│   └── radix_tree_index.h/cc        # 离线 Radix 树索引
+├── liteHit/              # 轻量多容量命中率核心
+│   ├── lite_hit.h/cc                # Full/Mamba 共享的容量无关 weighted LRU 核心
+│   ├── lite_hit_linear.h/cc         # Linear state 恢复点与写入策略（无独立 LRU 状态）
+│   ├── lite_hit_ttl.h/cc            # 包裹 LiteHit 的固定 TTL decorator（epoch/watermark）
+│   ├── weighted_lru_pool.h/cc       # 字节加权 LRU 池（typed key：Full / Linear）
 │   └── dynamic_fenwick_tree.h/cc    # reuse-distance 用的 order-statistics Fenwick
 ├── eviction_policy/      # 驱逐策略层
 │   ├── base.h                   # 策略基类
@@ -156,7 +159,9 @@ kv_cache_manager/optimizer/
 
 在线服务协议定义在 `kv_cache_manager/protocol/protobuf/optimizer_service.proto`，由 service 层转换为 optimizer online config/runtime 对象。
 
-full-attention TraceQuery 只把完整 block 放入 `block_keys`，并用 `input_token_len` 传入包含尾部 token 的原始输入长度。Online Manager 用 full location spec group 的固定字节 charge 将 `capacity_gb` 向下取整为 block 容量，再把同一请求交给 LiteHit；请求级与累计命中率均为 `prefix_hit_blocks * block_size_tokens / input_tokens`。旧客户端缺少长度时兼容假设没有尾部 token。full-attention 组配置 `ttl_seconds != 0` 时，固定 TTL 以墙钟时间叠加在 LiteHit 之上（口径与 `TtlCacheIndexerWrapper` 一致）；linear attention 的统计口径和 TTL 行为保持 legacy 路径不变。
+full-attention TraceQuery 只把完整 block 放入 `block_keys`，并用 `input_token_len` 传入包含尾部 token 的原始输入长度。Online Manager 与 linear attention 一样只保存 byte 容量；核心默认 byte-step 可无损压成 Full-only block-RLE，最终投影时再用 full location spec group 的固定字节 charge 做一次 floor。请求级与累计命中率均为 `prefix_hit_blocks * block_size_tokens / input_tokens`。旧客户端缺少长度时兼容假设没有尾部 token。
+
+linear attention（`linear_step > 0`）在同一个 LiteHit 上启用 Linear state 策略：Full block 与 Linear state 是两个独立对象，但共享**同一个 recency 和总字节预算**；容量轴是总字节而非 block 数，命中语义是“从某个 Linear state 恢复”。`LiteHit` 本身没有时间概念；外层 `TtlLiteHit` decorator 用共享 epoch/watermark 同时过滤 Full 与 Linear state，age 达到组 TTL 时从 weighted LRU 可见集合中失效。在线使用墙钟，离线使用 trace 时间戳，TTL 为 0 时 decorator 透明透传。
 
 ---
 

kv_cache_manager/optimizer/index/BUILD

@@ -16,48 +16,3 @@ cc_library(
         "//kv_cache_manager/optimizer/analysis",
     ],
 )
-
-cc_library(
-    name = "cache_indexer",
-    srcs = [
-        "online/lru_cache_indexer.cc",
-    ],
-    hdrs = [
-        "online/cache_indexer.h",
-        "online/lru_cache_indexer.h",
-    ],
-    deps = [
-        "//kv_cache_manager/common:logger",
-        "//kv_cache_manager/common/cache",
-    ],
-)
-
-cc_library(
-    name = "ttl_cache_indexer_wrapper",
-    srcs = [
-        "online/ttl_cache_indexer_wrapper.cc",
-    ],
-    hdrs = [
-        "online/ttl_cache_indexer_wrapper.h",
-    ],
-    deps = [
-        ":cache_indexer",
-        "//kv_cache_manager/common:timestamp_util",
-    ],
-)
-
-cc_library(
-    name = "cache_indexer_factory",
-    srcs = [
-        "online/cache_indexer_factory.cc",
-    ],
-    hdrs = [
-        "online/cache_indexer_factory.h",
-    ],
-    deps = [
-        ":cache_indexer",
-        ":ttl_cache_indexer_wrapper",
-        "//kv_cache_manager/common:env_util",
-        "//kv_cache_manager/common:logger",
-    ],
-)