Memory snapshots: Checkpoint/restore for sub-second startup

Modal has introduced memory snapshots to reduce serverless GPU container cold starts by capturing a container’s filesystem changes and full process state just before it accepts requests, then restoring that state later without rerunning costly initialization work such as Python imports. Built on gVisor’s checkpoint/restore capabilities, the approach is especially effective for workloads like PyTorch, whose imports trigger tens of thousands of filesystem-related system calls; Modal combines restored memory mappings with prioritized background page loading and aggressive caching to accelerate startup. Tests show snapshot restores averaging roughly 2.5 times faster than standard starts, reducing a Stable Diffusion function from about 13 seconds to 3.5 seconds and a simple PyTorch import from roughly five seconds to near one second. Snapshots are created on demand and may be specific to compatible worker hardware, CPU features, NVIDIA driver versions, and runtime versions, so Modal manages their lifecycle and falls back to ordinary startup if restoration fails. The feature requires applications to tolerate paused and reused process state, cannot preserve live network connections or GPU state, and therefore supports lifecycle hooks that snapshot CPU-side model setup while initializing GPU memory after restoration.

Use this post, company, and trend context to find content marketing opportunities, perform competitive analysis, or address product feature gaps via the Plushcap MCP server or the Plushcap API.