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SGLang vs. vLLM: Prefix Caching Performance Showdown

SGLang and vLLM are two systems designed to optimize LLM inference, particularly through prefix caching. SGLang utilizes RadixAttention, a CPU-based prefix cache that stores prompt and answer KV caches in a radix tree, allowing shared prompt beginnings to reuse stored memory. vLLM employs a similar automatic prefix caching mechanism that hashes KV cache blocks, but it can only reuse full blocks, limiting its effectiveness for partial prefix matches. Benchmarks show mixed results, with some indicating significant speedups for SGLang in specific shared-prefix scenarios, while others show vLLM performing comparably, especially with its own caching improvements. AI

IMPACT Optimizations like prefix caching in SGLang and vLLM can significantly improve LLM inference speed and efficiency, potentially lowering operational costs and enabling faster response times for applications.

RANK_REASON Comparison of two open-source LLM inference systems focusing on a specific technical feature (prefix caching). [lever_c_demoted from research: ic=1 ai=1.0]

Read on dev.to — LLM tag →

AI-generated summary · Google Gemini · from 1 sources. How we write summaries →

SGLang vs. vLLM: Prefix Caching Performance Showdown

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Comparison of two open-source LLM inference systems focusing on a specific technical feature (prefix caching). [lever_c_demoted from research: ic=1 ai=1.0]
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  1. dev.to — LLM tag TIER_1 English(EN) · Abdul Rehman ·

    SGLang vs vLLM: what prefix caching really saves

    <p>SGLang vs vLLM mostly comes down to one question: how much of your prompt do your requests have in common? SGLang is built around a prefix cache called RadixAttention, and vLLM offers a similar feature called automatic prefix caching. Where requests share long openings, both s…