What is a real-time kernel and how can it benefit your company?

Performance is not always easily measured. Part of the reason for this is the use case. Take, for example, the desktop versus server use case. You might think that a desktop could benefit from the same technology that helps boost a server's performance so that it can work with large amounts of data more quickly and reliably.

After all, isn't it fast, well, fast? Clear. But not all speed needs are equal. Case in point, the real-time kernel .

What is a real-time kernel?

In June 2023, it was announced it was releasing Real-Time Linux, which took advantage of a real-time kernel.

In this LinkedIn discussion , Pablo Mesa, COO at Ascend, says about real-time kernels (and real-time operating systems): “RTOSs also excel at optimizing resource utilization. By intelligently scheduling tasks based on priority, urgency and duration, they improve efficiency and ensure optimal performance. This capability is valuable in scenarios where time is of the essence, such as industrial control systems.”

But what exactly is a real-time kernel? Essentially, a real-time kernel (RTK) is about preventing latency (delay). An RTK manages a CPU's timing to ensure that time-critical events can be processed with a high level of efficiency. This does not mean that an RTK is superior to a traditional kernel, but rather that it focuses on very specific business or system requirements.

What does all this mean? Simply put, it means that an RTK is very predictable. This is especially important in use cases such as IoT, big data, machine learning, artificial intelligence, process automation, telecommunications and robot control systems. An RTK can be a solid option in any use case where latency may be an issue.

However, not every type of technology is suitable for every use case. An RTK is a perfect example of this. While you might think that minimal (almost zero) latency would be great for virtually any computer that requires very fast processing, that assumption would be incorrect.

The disadvantages of an RTK clearly illustrate that it is not ideal for all use cases. These disadvantages include:

• Requires much more (and highly complex) configuration to be useful
• Not compatible with all hardware
• Not suitable for software development or debugging
• Is less efficient with multitasking
• Can be unpredictable if not configured and deployed correctly
• Does not work well with many user applications

While there are some desktop use cases where an RTK may be advantageous (such as audio and video production), applications used in these instances must support an RTK, and there is no guarantee of this.

One of the biggest problems with using an RTK as a desktop solution is that general-purpose operating systems require features and characteristics that cannot work with the real-time latency guarantees found in an RTK. Because of the way it works, tasks with low priority tend to be ignored for long periods of time. A desktop operating system must be able to work with a multitude of applications from different vendors while still offering an acceptable level of performance.

An RTK is very specific for this, and a general purpose operating system would end up performing poorly under these conditions.

However, a purpose-built operating system (such as those for IoT devices) can benefit greatly from RTKs due to the inherent low latencies and scheduling priorities. At the end of the day, it's not just about speed, but also about time and fairness of the process.

The benefits of a real-time kernel

Once you see the benefits of an RTK, everything should fall into place for you and/or your development team. These benefits include:

• All processes are guaranteed to return or fail within a certain period of time.
• Deterministic task scheduling means that tasks are always executed in a timely and predictable manner.
• Reduced latency dramatically minimizes the time between the occurrence of an event and the associated response.
• Task prioritization allows an administrator or developer to assign specific priorities to ensure that all critical tasks are performed first.
• Resource management (such as memory allocation, inter-task communication, and task synchronization) has been greatly improved.
• Greater fault tolerance means that errors and exceptions are handled more gracefully, which improves the reliability of a system.
• Portability means that RTKs are available for multiple platforms and architectures.
• Modular by design means that features and components can be added or removed as needed.
• High scalability means you can scale depending on your needs.

When should your company use a real-time kernel?

As we already said, not every use case is ideal for an RTK. Ultimately, it comes down to latency and predictability. If you have a scenario where you need data processed in real time (like in edge computing), an RTK might be the best option.

These types of use cases are highly specialized, so you have some specific processes that should have very high priority.

Some very obvious examples of where an RTK can be successfully deployed include:

• Industrial automation
• Autonomous driving
• Healthcare (such as life support devices)
• Smart energy grids
• Aerospace and defense
• Telecommunications (such as call processing)
• Financial trading
• Multimedia and games

The pitfalls of real-time kernels

The biggest problem when employing an RTK is having engineers, administrators, and developers with the skills needed to properly configure and deploy them. While you can find operating systems built specifically as real-time platforms, if your use case doesn't exactly fit that purpose, you'll have to do some optimizations. Without a trained team, this can be a challenge.

And of course, as we mentioned earlier, RTKs are not in general use. If you deploy an RTK for a general purpose (hoping to benefit from extremely low latency), you will find that many applications and services suffer a dramatic degradation in performance.

Furthermore, the cost of a real-time kernel can be prohibitive. Given that you will not be running this kernel on commodity hardware, you will incur the initial cost of systems that can benefit from these types of kernels.

RTKs can also be very limiting. As we already mentioned, they usually have a specific purpose, so your administrators and developers need to be able to work with a kernel that may have a very narrow focus. At the same time, RTKs are often very inflexible. Therefore, if you think you are going to employ an RTK and bend it to meet needs outside of its intended purpose, you will find the task quite challenging.

Finally, although you can get a high-performance system with an RTK, delivery time can be prolonged. Because RTKs require a very special skill set, it will take your development teams longer to get everything ready for production… especially if they are learning as they go.

Conclusion

Real-time kernels offer some surprising advantages for specific use cases and if your company falls under the auspices of such a use case, an RTK could be the ideal option. And since you can find many Linux distributions that offer RTK options, you won't have to spend an excessive amount of your budget on the operating system.