News: 0001629537

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Arm C1-Ultra Scheduling Model Merged For LLVM/Clang 23

([Arm] 6 Hours Ago C1-Ultra)


Merged recently to the latest LLVM/Clang compiler development tree is the Arm C1-Ultra scheduling model for helping with delivering optimal binaries for that flagship next-gen Arm mobile CPU.

The Arm C1-Ultra is the flagship model of Arm's [1]C1 CPUs announced last September . Now for going beyond the basic compiler enablement for the Arm C1 that [2]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 [3]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 [4]LLVM Git ahead of the LLVM 23 stable release later in the year.



[1] https://www.phoronix.com/news/Arm-Lumex-Platform-C1

[2] https://www.phoronix.com/news/LLVM-Clang-22-Branched

[3] https://www.arm.com/products/silicon-ip-cpu/c1-ultra

[4] https://github.com/llvm/llvm-project/commit/b6c9cbe69d96ac80c3ed42b09c19dddc15df464e



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