IBM Power Systems for Linux: What sets Power apart

By | 3 minute read | May 18, 2020

The myth that “Linux on x86 is different from Linux on Power” has been promoted by those who wanted you to believe that if you invested in Linux on IBM Power Systems you would get an inferior product that wasn’t “real” Linux, and your applications wouldn’t work as they should. In an earlier post, I dispelled that myth by showing that the basic components of any Linux distribution, from the kernel to the tools used to administer the system and develop applications, are the same, regardless of the underlying hardware platform.

That said, the underlying hardware platforms (the system architectures) are not the same. The chip architectures and instruction sets are different, and while these differences don’t affect the application functionality (HANA is HANA and Mongo is Mongo), they do affect the performance, reliability and scalability of these systems.

Linux on x86 is different from Linux on Power because applications running on the IBM Power/Linux platform are usually faster, more reliable, more scalable, more secure and require fewer cores and physical systems. The underlying system architecture is the reason why.

The Linux kernel

In a Linux kernel, there are sections of code that take advantage of unique features of a system architecture. When the Linux kernel is built and compiled for IBM Power Systems, it’s aware of these attributes, like reliability, availability, serviceability (RAS) and security options not found on x86 systems. It uses them to provide mission-critical capabilities that can result in significantly higher performance, reliability and capacity.

There’s a similar section of code available in a Linux kernel to exploit x86 architectural features. The challenge x86 vendors face is that the Linux kernel doesn’t create a section of code for each vendor and their special features. So, Linux distributions for x86 systems have to be built to the lowest common denominator for the x86 system architecture.

The analytics and big data advantage

Analytics and big data are at the heart of applications driving innovation around the world today. The efficient management of data within these applications is critical to their performance, and this is where IBM Power Systems have a significant advantage over x86 systems. Consider the following:

  • Power Systems support up to eight-way simultaneous multithreading, while x86 architecture only supports two-way hyperthreading. Because of this, Power Systems are more highly utilized, providing more throughput per core, a key advantage given that most databases are multi-threaded.
  • Firmware in Power Systems helps address latency issues found in nonuniform memory access (NUMA) architectures by attempting to keep core and memory allocations together when virtual machines (VMs) are created, providing significant benefits to database applications where memory access is high.
  • System performance is greatly increased by efficiently managing the movement of data from main memory to cache memory. Power Systems provides a highly efficient cache system that includes a very large on-processor victim cache shared by all cores on the processor, offering high probability that data will be in cache when needed.
  • GPUs are critical to the performance of analytics, AI and high-performance computing (HPC) applications. On x86 systems, GPUs are connected through the PCIe interface and are limited to 32 GB/s. For Power Systems, a direct, high-speed, memory coherent connection to integrated NVIDIA GPUs running at 300 GB/s is available. This can provide up to a 7x performance increase for analytics, AI and HCP applications.

Get the most from your system architecture

It’s critical that Linux application development, execution and management be guaranteed across different system architectures. It’s also important that Linux distributions have the ability to exploit features that are unique to a system architecture while not compromising that guarantee. Otherwise, Linux distributions would be reduced to supporting the least common denominator of a system architecture, eliminating the rich set of features at the heart of IBM Power Systems and the benefits those features bring to your solution.

IBM Systems Lab Services has a team of highly experienced consultants ready to help you get the most out of your Linux on Power Systems investments. Reach out today if you have questions or are looking for support.

A special thanks to Ron Gordon from Mainline and Steve Roberson from IBM for their contributions to this post.