Revati: Transparent GPU-Free Time-Warp Emulation for LLM Serving

Fuente: arXiv
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Main Authors: Agrawal, Amey, Yadav, Mayank, Kumar, Sukrit, Agrawal, Anirudha, Ghai, Garv, Bera, Souradeep, Pinto, Elton, Gambhira, Sirish, Adain, Mohammad, Sohrab, Kasra, Antonanzas, Chus, Tumanov, Alexey
Format: Preprint
Published: 2026
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author Agrawal, Amey
Yadav, Mayank
Kumar, Sukrit
Agrawal, Anirudha
Ghai, Garv
Bera, Souradeep
Pinto, Elton
Gambhira, Sirish
Adain, Mohammad
Sohrab, Kasra
Antonanzas, Chus
Tumanov, Alexey
author_facet Agrawal, Amey
Yadav, Mayank
Kumar, Sukrit
Agrawal, Anirudha
Ghai, Garv
Bera, Souradeep
Pinto, Elton
Gambhira, Sirish
Adain, Mohammad
Sohrab, Kasra
Antonanzas, Chus
Tumanov, Alexey
contents Deploying LLMs efficiently requires testing hundreds of serving configurations, but evaluating each one on a GPU cluster takes hours and costs thousands of dollars. Discrete-event simulators are faster and cheaper, but they require re-implementing the serving system's control logic -- a burden that compounds as frameworks evolve. We present Revati, a time-warp emulator that enables performance modeling by directly executing real serving system code at simulation-like speed. The system intercepts CUDA API calls to virtualize device management, allowing serving frameworks to run without physical GPUs. Instead of executing GPU kernels, it performs time jumps -- fast-forwarding virtual time by predicted kernel durations. We propose a coordination protocol that synchronizes these jumps across distributed processes while preserving causality. On vLLM and SGLang, Revati achieves less than 5% prediction error across multiple models and parallelism configurations, while running 5-17x faster than real GPU execution.
format Preprint
id arxiv_https___arxiv_org_abs_2601_00397
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle Revati: Transparent GPU-Free Time-Warp Emulation for LLM Serving
Agrawal, Amey
Yadav, Mayank
Kumar, Sukrit
Agrawal, Anirudha
Ghai, Garv
Bera, Souradeep
Pinto, Elton
Gambhira, Sirish
Adain, Mohammad
Sohrab, Kasra
Antonanzas, Chus
Tumanov, Alexey
Distributed, Parallel, and Cluster Computing
Machine Learning
Deploying LLMs efficiently requires testing hundreds of serving configurations, but evaluating each one on a GPU cluster takes hours and costs thousands of dollars. Discrete-event simulators are faster and cheaper, but they require re-implementing the serving system's control logic -- a burden that compounds as frameworks evolve. We present Revati, a time-warp emulator that enables performance modeling by directly executing real serving system code at simulation-like speed. The system intercepts CUDA API calls to virtualize device management, allowing serving frameworks to run without physical GPUs. Instead of executing GPU kernels, it performs time jumps -- fast-forwarding virtual time by predicted kernel durations. We propose a coordination protocol that synchronizes these jumps across distributed processes while preserving causality. On vLLM and SGLang, Revati achieves less than 5% prediction error across multiple models and parallelism configurations, while running 5-17x faster than real GPU execution.
title Revati: Transparent GPU-Free Time-Warp Emulation for LLM Serving
topic Distributed, Parallel, and Cluster Computing
Machine Learning
url https://arxiv.org/abs/2601.00397