The deceleration of Moore's Law and the rapid growth of the smartphone market have shifted the balance in the processor market. High-end smartphones have increased the performance of smartphone architectures, meaning that ARM architecture is increasingly becoming an option for servers too. Microsoft has therefore announced that it will drive innovation in its data centers through the use of ARM processors. "We have worked with several ARM server manufacturers such as Qualcomm and Cavium to optimize their silicon for our applications," says Leender van Doorn from Microsoft.

Accordingly, Microsoft has evaluated the ARM processors under real load and is impressed by the high number of instructions that are processed per clock cycle and the density of cores and threads that are now available in an ARM server. According to Microsoft, the connectivity options and the high level of integration of ARM processors also speak in favor of ARM server processors. "The scalability that some cloud services require, such as the number of machines assigned to a service, make it more economical to adapt the hardware to the software than vice versa - even if that means changing the instruction set," writes Microsoft engineer Lender van Doorn in his Azure blog. In addition to these hardware facts, there are also a number of "soft" reasons that speak in favor of the ARM architecture for Microsoft:

• There is a diverse landscape of ARM server vendors, which makes for lively development activity around cores, thread counts, cache sizes, hardware accelerators, instructions and connectivity options
• There is a large developer community and an extensive software base. ARM servers benefit from the software systems that have been developed for high-end smartphones. This proven development system has made it much easier for Microsoft to port its Azure services to the ARM architecture.
• Microsoft sees ARM as a promising approach for the further development of the instruction set. While the possibilities of out-of-order execution will soon be exhausted, new data flow architectures are emerging on ARM that will further increase performance without compromising compatibility with existing software.

Windows Server on Qualcomm and Cavium hardware

According to Microsoft, the ARM platform proves its worth above all in cloud services, especially search and indexing, storage systems, databases, big data and machine learning. All of these applications benefit from high computing throughput. To operate these cloud services, Microsoft has ported a version of Windows Server to the ARM architecture - but only for internal purposes. The port also includes runtime environments for programming languages and middleware.

At the OCP US Summit (Open Compute Project), Qualcomm showed a demonstration on a Centriq 2400 server processor, which is manufactured using the 10 nm process and has 48 ARMv8-A cores developed by Qualcomm itself. The processor also contains Qualcomm's fastest interface for memory, network and peripherals.

64-bit server SoC 'Thunder X2' from Cavium with ARMv8-A architecture.

© Cavium

Cavium also gave a demonstration with a ThunderX2 server processor. This chip is in its second generation and also uses the ARMv8-A architecture. This server SoC also has its own cores developed by Cavium and can address more than 1 TB of RAM with its memory interfaces. Cavium also speaks of "hundreds of integrated hardware accelerators for encryption, storage, communication and virtualization.