HN · HACKER_NEWS// 7d agoBENCHMARK RESULT

Linux 7.0 Slashes PostgreSQL Throughput in Half

AWS says the current Linux 7.0 development kernel can cut PostgreSQL throughput to roughly 0.51x on Graviton4, with the slowdown tied to a preemption-mode change that increases time spent in a user-space spinlock. The proposed kernel-side fix looks unlikely, so PostgreSQL may need to adapt instead.

// ANALYSIS

This smells like a kernel-vs-runtime boundary fight, not a simple bug fix. If the revert gets rejected, the pain shifts to PostgreSQL and any workload that leans on similar locking patterns.

–The regression was bisected to Linux 7.0’s restriction of available preemption modes, specifically the move away from PREEMPT_NONE as a default.
–Peter Zijlstra’s suggested path is to use rseq slice extension support, which pushes the workaround into user space rather than undoing the kernel change.
–That makes this more than a one-off benchmark blip: database runtimes may need code changes to stay fast on newer kernels.
–The impact appears workload-specific, but PostgreSQL is common enough that even a narrow regression becomes an ecosystem problem.
–If Linux 7.0 stable ships before PostgreSQL adapts, cloud operators could see a real performance cliff on affected deployments.

// TAGS

linux-7.0postgresqlbenchmarkopen-source

DISCOVERED

7d ago

2026-04-05

PUBLISHED

7d ago

2026-04-05

RELEVANCE

8/ 10

AUTHOR

crcastle