AWS Engineer Reports PostgreSQL Performance Halved By Linux 7.0, But A Fix May Not Be Easy

An AWS engineer reported that PostgreSQL throughput on the Linux 7.0 development kernel is about half that of prior kernels.

The regression was traced to Linux 7.0 restricting available preemption modes, increasing time spent in a user-space spinlock.

A patch to restore PREEMPT_NONE was posted, but a core maintainer suggested PostgreSQL should adopt the RSEQ slice extension instead.

Linux 7.0 stable is due in about two weeks and will power Ubuntu 26.04 LTS, so affected PostgreSQL workloads may see reduced performance until updated.