Speaker
Description
Checkpoint/Restore (C/R) is increasingly used for both startup acceleration (restoring pre-warmed snapshot instances on demand) and live migration. However, deploying static snapshots or migrating tasks across heterogeneous clusters creates severe runtime bottlenecks when source and target nodes possess differing CPU capabilities. While CRIU and container runtimes can accurately preserve memory state, handling CPU feature consistency and safe architectural state restoration across diverse hardware remains an unsolved problem at the kernel boundary.
This session will focus on two critical kernel/userspace interaction challenges:. While CRIU and container runtimes can accurately capture and restore process states and kernel resources, handling CPU feature consistency and safe architectural state restoration across diverse hardware remains an unsolved problem at the kernel boundary.
This session will focus on two critical kernel/userspace interaction challenges:
1. HWCAP Inheritance & Feature Discovery: Examining feature detection failures when restoring snapshots on target nodes with different CPU features, and reviewing proposed mechanisms to inherit or mask hardware capabilities (HWCAP/HWCAP2 via auxv) across execve().
2. Restoring Extended Signal Frame States: Analyzing edge cases where tasks contain in-flight signal frames with architecture-specific CPU state on their stack. We will discuss why rigid kernel-side frame validation during rt_sigreturn causes restoration failures across hardware generations, and propose flexible validation strategies that prevent state corruption while preserving ABI safety.
Goal: Align kernel, container, and language runtime maintainers on kernel-assisted CPU feature control and flexible signal-context restoration to make snapshot-based fast-booting and live migration robust across heterogeneous fleets.