An engineer from Amazon/AWS reported a significant performance regression in PostgreSQL when running on the nearly finalized Linux 7.0 kernel, with throughput dropping to about half of previous kernel versions. The regression, observed on a Graviton4 server, is attributed to increased time spent in a user-space spinlock due to changes in preemption modes in Linux 7.0. A patch to revert to PREEMPT_NONE as the default preemption model has been submitted but may not be adopted. Peter Zijlstra suggested that PostgreSQL should adapt to utilize the Restartable Sequences (RSEQ) time slice extension to mitigate the performance drop. If this adaptation is accepted, the responsibility for the performance decline may shift to PostgreSQL, potentially affecting users until the database is updated. The stable release of Linux 7.0 is expected in about two weeks, coinciding with the launch of Ubuntu 26.04 LTS.