Linux 6.15 lands fix for 3x Nginx regression

a year ago

Linux 6.15 kernel merged a fix for a severe performance regression affecting Nginx and other applications.
The regression caused up to a 3x performance drop in Nginx HTTPS performance and impacted other workloads like Netperf, Ethr, OpenFOAM, ClickHouse, PostgreSQL, and Memcached.
The issue was initially hard to diagnose but was resolved within 24 hours thanks to contributions from SUSE engineer Vlastimil Babka and other kernel developers.
Testing confirmed the patch resolved the regression, with some workloads even performing slightly better post-fix.
The regression was linked to a specific commit and was more noticeable with newer GCC compilers.
Linus Torvalds quickly merged the fix due to the severity of the performance impact.

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