Linux developers are preparing to make Intel's ancient MultiMedia eXtensions irrelevant as the kernel targets the removal of its last remaining MMX-optimized code. The...
The mainline Linux kernel is scheduled to drop its final legacy MMX optimizations with the upcoming 7.5 release.
Finalizing the Removal of 1990s Instructions
Linux developers are preparing to make Intel’s ancient MultiMedia eXtensions irrelevant as the kernel targets the removal of its last remaining MMX-optimized code. The change is slated to merge into the Linux 7.5 kernel cycle, moving the mainline operating system further away from hardware architectures introduced in the late 1990s.
Google’s Eric Biggers has a patch prepared to strip out the obsolete MMX-optimized code from the kernel’s software RAID xor code path. Once merged, systems running modern software with up-to-date kernels on vintage silicon will drop explicit vector routines for those specific instruction sets.
Impact on Legacy Hardware and Software RAID
The deprecation targets hardware such as the Intel Pentium MMX, Pentium II processors, and the AMD K6 series that rely on the late-90s instruction set. When Linux 7.5 arrives in 2027, users operating these legacy machines who cannot benefit from newer Instruction Set Architectures like SSE or better will experience a fallback. Specifically, those running Linux software RAID on these chips will default to the scalar code path rather than utilizing optimized MMX routines.
Authoritative specifications and documentation confirm that the patch targets this specific corner of the legacy codebase, marking a definitive shift as decades-old hardware optimizations are phased out of the active kernel tree.
What Remains Unconfirmed
Exact release timelines for the point releases leading up to the 2027 launch of Linux 7.5 remain unconfirmed beyond the targeted merge window. Further specifics regarding potential deprecations for other equally ancient instruction sets outside of this specific software RAID xor code have not been detailed in current developer documentation.
Frequently Asked Questions
Q1: When is Linux 7.5 expected to be released?
The Linux 7.5 kernel is scheduled for release in 2027.
Q2: Which processors are affected by the removal of MMX code?
The changes affect legacy hardware like the Intel Pentium MMX, Pentium II, and AMD K6 series.