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upstream_ref/xllm/docs/en/features/prefix_cache.md

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+# Prefix Cache Optimization
+
+## Feature Introduction
+xLLM supports prefix cache matching. The prefix cache is based on `murmur_hash` and uses an LRU eviction policy, delivering superior matching efficiency and increased prefix cache hit rates.
+Additionally, the prefix cache has been optimized to support the `continuous_scheduler`, `chunked_scheduler`, and `zero_evict_scheduler`. The cache is updated immediately after prefill operations, enhancing matching timeliness. For the `chunked_scheduler`, multi-stage chunked prefill matching is supported, reducing computational overhead and minimizing KV cache usage as much as possible.
+
+## Usage
+The prefix cache is implemented in xLLM and exposed through gflags parameters to control its functionality.
+
+- Enable prefix cache with specific policy and settings:
+```
+--enable_prefix_cache=true
+```
+
+## Performance Impact
+After enabling prefix cache, on the Qwen3-8B model with a TPOT constraint of 50ms, the E2E latency **decreased by 10%**.
+
+!!! warning "Note"
+    PD separation scheduler is not currently supported.