● Covered by 1 source · 1 reportLow impact1 neutral
Linux 7.5 to Remove Last Intel MMX Optimizations from Software RAID XOR Code
Key points
- Linux 7.5 will remove the last MMX optimizations.
- The affected code is in the software RAID XOR function.
- MMX was introduced by Intel in 1997 with Pentium chips.
- The change reduces kernel code by over 800 lines.
Final MMX Code Removal
Linux developers are set to eliminate the last remaining Intel MultiMedia eXtensions (MMX) optimized code from the kernel. This change will specifically target the software RAID XOR code and is expected to be merged into mainline Linux 7.5, which has an anticipated release in 2027. This action effectively phases out support for the 30-year-old instruction set within the operating system.
Historical Context of MMX
Intel introduced MMX with its Pentium chips in January 1997. While initially marketed as 'MultiMedia eXtensions,' Intel later trademarked 'MMX' as a meaningless initialism. A court document during a trademark dispute with AMD suggested MMX stood for 'Matrix Math Extensions.' Rival x86 processors from AMD, Centaur, Cyrix, Rise, and Transmeta eventually integrated MMX instructions to compete in the multimedia market.
Impact and Code Housekeeping
The removal of MMX optimizations is considered a routine code housekeeping measure. Very few users are expected to run modern Linux kernels on the ancient Pentium MMX and Pentium II chips that relied on these optimizations. This change will result in a reduction of over 800 lines of code in the kernel, replaced by just 12 lines. Most other MMX-optimized code was removed from Linux over five years ago.
Continued Functionality for Older Hardware
Even after this change, users with older Pentium systems can still utilize software RAID. However, it will operate without the MMX fast path, meaning performance for that specific function will not be optimized for MMX instructions.
✨ This summary was generated by AI from the outlets' reporting listed below. It is not independently verified and may contain errors — check the original sources. How BrevFeed works →
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Reporting from
Linux developers are preparing to remove the final Intel MMX-optimized code from the kernel's software RAID XOR function, a change expected in Linux 7.5, which is anticipated for release in 2027. This removal marks the end of support for the 30-year-old MMX extensions, introduced with Pentium processors, as modern systems no longer utilize them.