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Understanding SGLang's Radix Cache, the LeetCode Way

Overview

What is Radix Cache?

When an LLM processes a prompt, it computes a Key and Value vector for every token — the KV cache. If many requests share the same system prompt, recomputing its KV cache from scratch each time is wasteful. Radix Cache stores these computed prefixes in a Radix Tree and reuses them across requests, which is one of the main reasons SGLang achieves high throughput.

Why Read mini-sglang Instead of SGLang Directly?

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module Parser where

newtype Parser a = P { parse :: String -> [(a, String)] }

instance Functor Parser where
    fmap g p = P (\inp -> case parse p inp of
        [] -> []
        [(v, out)] -> [(g v, out)])

instance Applicative Parser where

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module Parser where

newtype Parser a = P { parse :: String -> [(a, String)] }

instance Functor Parser where
    fmap g p = P (\inp -> case parse p inp of
        [] -> []
        [(v, out)] -> [(g v, out)])

instance Applicative Parser where

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