Spectre V2 & Meltdown Linux Fixes Might Get Disabled For Atom N270 & Other In-Order CPUs

There's a suggestion/proposal to disable the Spectre Variant Two and Meltdown mitigation by default with the Linux kernel for in-order CPUs.

If you have an old netbook still in use or the other once popular devices powered by the Intel Atom N270 or other in-order processors, there may be some reprieve when upgrading kernels in the future to get the Spectre/Meltdown mitigation disabled by default since these CPUs aren't vulnerable to attack but having the mitigation in place can be costly performance-wise.

A user volleyed the suggestion on the kernel mailing list to get Retpolines and KPTI disabled by default for the N270 / in-order CPUs. Currently the support is enabled by default for all Intel CPUs, but can be disabled easily by setting nopti spectre_v2=off as kernel command-line parameters.

Kernel developer Pavel Machek suggested more scientifically measuring the performance difference rather than just "feeling" the impact while browsing the web. But he agrees that workarounds shouldn't be applied to non-buggy hardware.

We'll see what happens for this default change to benefit primarily old netbook/nettop Linux users.