Fedora 40 Looks To Provide Optimized x86_64 Binaries For Different HWCAPs

In addition to Ubuntu exploring the possibility of x86_64-v3 builds/packages, a proposal has been raised for Fedora Linux with its current Fedora 40 cycle to provide the ability to offer optimized x86_64 (AMD64) binaries based upon the CPU's x86_64 micro-architecture feature level.

The proposal, which still needs to be approved by the Fedora Engineering and Steering Committee (FESCo), would allow optimized x86_64 libraries and application binaries to be automatically utilized on supported Intel and AMD CPUs when on a supported feature level and a package having an optimized version available. This x86_64 micro-architecture feature level support is similar to what's already been in use by the likes of openSUSE Tumbleweed and Intel's Clear Linux.

The change proposal explains:

"Additional paths will be inserted into the search path used for executables on systems which have a compatible CPU. Those additional paths will mirror the AMD64 / x86_64 "microarchitecture levels" supported by the glibc-hwcaps mechanism: x86-64-v2, x86-64-v3, x86_64-v4. Systemd will be modified to insert the additional directories into the $PATH environment variable (affecting all programs on the system) and the equivalent internal mechanism in systemd (affecting what executables are used by services). Individual packages can provide optimized libraries via the glibc-hwcaps mechanism and optimized executables via the extended search path. This optimized code will be used if the CPU supports it. Which packages provide the optimized code and at which level will be made by individual package maintainers based on benchmark results."

It's an exciting F40 proposal and hopefully it receives the FESCo blessing as well as package maintainers taking the extra steps of evaluating the performance benefits of targeting the higher micro-architecture feature levels.

As we enter 2024 it's great seeing more Linux distribution vendors finally moving toward upping their x86_64 baseline and/or augmenting their x86_64 binaries with optional support for better tuned binaries for today's AMD/Intel processors.