IBM's new processor merges Arm and Z workloads on same cores

IBM has unveiled a new processor at the Hot Chips conference, representing a significant shift in mainframe architecture. The chip, set to power the next generation of IBM Z and LinuxONE systems, is the first mainframe processor with a dual-architecture design, allowing its cores to natively execute both Arm and IBM's own instruction sets.

This new design enables enterprises to run the rapidly growing ecosystem of Arm-native Linux software, including AI frameworks, directly alongside the mission-critical z/OS transaction-processing workloads that underpin global financial systems. This addresses the challenge of keeping mainframes relevant in an AI-centric era often dominated by other silicon architectures.

Instead of adding separate Arm cores, IBM engineered each core on the chip to be bilingual. The 11 cores can dynamically switch between Arm software mode and traditional Z software mode in nanoseconds. This integration allows for the simultaneous operation of critical enterprise software and a broader range of Arm applications on the same hardware.

The seamless switching between modes is facilitated by the open-source KVM hypervisor. Businesses can run Arm64 Linux virtual machines and Linux on Z virtual machines side-by-side. IBM claims the performance overhead from this switching is effectively zero due to its speed, measured on the nanosecond scale.

Built on an advanced 2-nanometer process, the processor features cores running above 5.7 GHz, alongside integrated AI inference accelerators and a dedicated data processing unit for I/O. IBM aims to leverage Arm's vast developer community of over 22 million to expand the software offerings for its mainframe systems.