Linux 7.1 Delivers Performance Regression Fix For Sheaves
The Linux 7.1 kernel is bringing performance improvements for 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 an opt-in feature but since Linux 7.0 is 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 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 SLAB updates for Linux 7.1, this Sheaves work is now in place to help with the performance.
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 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 SLAB updates for Linux 7.1, this Sheaves work is now in place to help with the performance.