The [1]Linux 7.1 kernel is bringing performance improvements for [2]Sheaves , the per-CPU caching layer introduced several kernel cycles ago (Linux 6.18) for better efficiency on today's high core count hardware. Sheaves began as [3]an opt-in feature but since Linux 7.0 is [4]now being used for all caches .

With the expanded use of Sheaves, regression reports have turned up in some scenarios and so for Linux 7.1 some regressions are hopefully now addressed. A recent focus was on improving Sheaves performance for systems with memory-less NUMA nodes. This work is ensuring Sheaves are properly used on CPUs belonging to memory-less NUMA nodes.

Motivating the performance work was [5]this bug report from a Red Hat engineer indicating a "severe performance regression" in cross-CPU Slab allocation on Linux 7.0. This code was too invasive to fix for Linux 7.0 so now the regression should be resolved with Linux 7.1.

As part of the [6]SLAB updates for Linux 7.1, this Sheaves work is now in place to help with the performance.



[1] https://www.phoronix.com/search/Linux+7.1

[2] https://www.phoronix.com/search/sheaves

[3] https://www.phoronix.com/news/Linux-6.18-Likely-Sheaves

[4] https://www.phoronix.com/news/Linux-7.0-Slab-Sheaves

[5] https://lore.kernel.org/all/aZ0SbIqaIkwoW2mB@fedora/

[6] https://lore.kernel.org/lkml/db0210a9-0bce-476b-920d-7e90f54fe72b@kernel.org/