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Sleeping 24 models cost 27 GB of an 80 GB GPU, and deduplicating the shared GPU context cut that footprint by 98.1 percent

AspireAI community · arXiv (IEEE HPCC 2026)
Model sleeping, the approach vLLM and SGLang use to get near-zero-cost scale-up by pausing pre-spawned engines, has a hidden cost: every sleeping model keeps its GPU context resident, and that cost grows linearly with the number of models. The measurements here are concrete, with vanilla vLLM sleep consuming up to 27 GB, 34 percent of an 80 GB GPU, for 24 models. PhOSv1 attacks the duplication instead of the models: the driver context can be shared across models and their GPU kernel binaries overlap heavily, so each engine's GPU context allocation is delegated transparently to a central daemon through API remoting. Sleeping 23 models then used 0.49 GiB instead of 25.67 GiB, a 98.1 percent reduction, with scale-up time similar to vanilla vLLM sleep mode. In a multi-model trace replay this reduced average time to first token from 146.82 to 19.09 seconds, an 87.0 percent improvement over vanilla vLLM limited by its sleep-cache budget. The measured sleep footprint excludes model weights, and the evaluation is single-server.
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