Is x86 ready to ACE it?

CPU designs must evolve to keep up with changing workloads. Sometimes, that evolution involves extending the instruction set to efficiently represent certain types of work. Intel’s AMX extension is one such example. AMX accelerates matrix multiplication for machine learning workloads by providing a set of 2D tile registers and configuration registers. Programmers can then configure specialized execution units (“accelerators”) to target matrix data in those tile registers. AMX was first implemented on Intel’s Sapphire Rapids server CPUs with a tile matrix multiply unit (TMUL) accelerator. Now, the x86 Ecosystem Advisory Group has written up a whitepaper and specification for ACE, which introduces a second accelerator type. While ACE is an AMX accelerator alongside TMUL, I’m going to call them “AMX” and “ACE” because TMUL was the only accelerator implementation that existed at AMX’s launch, and is still the only AMX accelerator available in hardware today. Documentation also tends to…