AWS Engineer Reports PostgreSQL Performance Halved by Linux 7.0 on Graviton4

Phoronix·high signal

An Amazon engineer found Linux 7.0 delivers ~0.51x PostgreSQL throughput on Graviton4 servers due to excessive time in user-space spinlocks, caused by Linux 7.0's simplification of preemption modes. Kernel maintainer Peter Zijlstra says the 'fix' is for PostgreSQL to adopt Restartable Sequences (RSEQ), shifting the burden to the database. With Linux 7.0 stable due in two weeks, high-core-count ARM64 deployments face a significant performance cliff until PostgreSQL is updated.