AWS Engineer Reports PostgreSQL Perf Halved by Linux 7.0, Fix May Not Be Easy (phoronix.com)

An AWS engineer says PostgreSQL performance drops to about half on near-final Linux 7.0 kernels, traced to scheduler/preemption changes that increase time spent in user-space spinlocks. A proposed kernel patch to restore the PREEMPT_NONE default may not fully land, with the original code author suggesting PostgreSQL should instead use Linux 7.0’s rseq time-slice support to reduce the impact. The article notes Linux 7.0 stable is expected in about two weeks, with Ubuntu 26.04 LTS also based on the same kernel line.