IBM unveils mainframe chip supporting both Arm and Z workloads on same cores

Dual-Architecture Mainframe Processor Introduced

IBM announced a new mainframe chip at the Hot Chips conference, marking a significant change in mainframe architecture. This processor is the first dual-architecture mainframe processor, capable of natively executing both IBM's instruction set and Arm's instruction set.

The chip will power the next generation of IBM Z and LinuxONE systems. It allows for the integration of Arm-native Linux software, including AI frameworks, with existing z/OS transaction-processing workloads on the same hardware.

Engineering for Instruction Set Compatibility

Instead of adding separate Arm cores, IBM engineered each of the chip's 11 cores to be bilingual. Each core can dynamically switch between Arm software mode and traditional Z software mode in nanoseconds, with no performance penalty.

This design enables mission-critical enterprise software to run alongside the broader ecosystem of Arm applications on the same chip.

Integration with Virtualization

The mechanism for switching between instruction sets relies on the open-source KVM hypervisor. Enterprises can run Arm64 Linux virtual machines and Linux on Z virtual machines side by side.

The hypervisor dispatches each virtual machine onto a physical core, and the core automatically flips into the corresponding mode.

Strategic Impact for Mainframe Systems

This announcement represents the first hardware milestone from a strategic collaboration between IBM and Arm, which was unveiled in April. The development addresses the challenge of integrating modern AI infrastructure, often built on Arm silicon, with the mainframe's role in processing regulated financial transactions.

The new chip aims to ensure the mainframe remains a relevant platform in an evolving technological landscape.