Linux 5.5 Lands Fix For The AppArmor Performance Regression
Written by Michael Larabel in Linux Kernel on 5 January 2020 at 08:46 AM EST. 10 Comments
Linux 5.5 as of this morning should have one less performance regression in tow if you are running on Debian/Ubuntu or otherwise having AppArmor enabled.

The Linux 5.5 bisected regression back around Christmas is now resolved as of last night's Git code for Linux 5.5.

With this set of AppArmor fixes is a change to only get a label reference if the fast path check fails. That in turn fixes the Linux 5.5 AppArmor performance regression.

It will be interesting to see now the performance cost of these 70+ benchmarks when toggling AppArmor. Hackbench should be in better shape and will be interesting to see now the overall cost of having AppArmor enabled on Linux 5.5 now that this regression is fixed up.

More benchmarks forthcoming of Linux 5.5 that will be releasing as stable around month's end. While it's been a bit bumpy on the performance front, Linux 5.5 has many exciting features/improvements. Linux 5.5-rc5 should be out this evening for those preferring tagged weekly snapshots.
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Michael Larabel is the principal author of and founded the site in 2004 with a focus on enriching the Linux hardware experience. Michael has written more than 20,000 articles covering the state of Linux hardware support, Linux performance, graphics drivers, and other topics. Michael is also the lead developer of the Phoronix Test Suite, Phoromatic, and automated benchmarking software. He can be followed via Twitter or contacted via

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