Well-known Linux kernel maintainer Greg Kroah-Hartman recently shared some interesting details about the impact of Meltdown and Spectre on his kernel.
According to some recent benchmarks performed by a user on some Linux systems running newer kernel versions under a specific network load, the new Linux 4.15 kernel appears to be between 7 and 9% faster than the 4.11 kernel.
However, if the new KPTI (Kernel Page-Table Isolation) code that mitigates the Meltdown security vulnerability is enabled in the 4.15 kernel, then performance is only 1 or 2% slower than on systems using the 4.11 kernel.
Therefore, all the developers who worked hard in recent months to rework the Linux kernel against the Meltdown and Spectre security vulnerabilities should be quite satisfied with their feat, as there have been numerous reports of the dramatic effects of these patches on systems.
Greg Kroah-Hartman recommends that anyone using a GNU/Linux distribution with a Linux kernel from an older, but long-term supported branch, such as 3.10, 4.4, or 4.9, upgrade to a newer version of the kernel as soon as possible.
As a reminder, the latest kernel version is 4.15, which was released over the weekend with many performance improvements and some new features. If your GNU/Linux distribution does not have the latest kernel in its repositories, you will need to download and compile the kernel manually.
