The Arm C1-Ultra is the flagship model of Arm's C1 CPUs announced last September . Now for going beyond the basic compiler enablement for the Arm C1 that previously landed into the LLVM 22 codebase , a proper scheduling model is now in place for the C1-Ultra.
The C1-Ultra scheduling model is derived from the Neoverse V3 scheduling model while making changes based upon Arm's software optimization guide for the C1-Ultra core. This should help in ensuring the best possible performance for binaries targeting this flagship Armv9.3-A CPU core.
Arm's C1-Ultra claims include +25% single thread performance over the Cortex-X925, +15% speed-up on average in real-world applications, and other big wins for this Armv9.3-A + SME2 design.
Those curious about this new C1-Ultra scheduling model can find it in LLVM Git ahead of the LLVM 23 stable release later in the year.