how load average is calculated in linux

In the Linux operating system, the load average is an important metric that measures the amount of work the CPU is doing over a given period of time. Load average is commonly used by system administrators to monitor the health of their servers and ensure that they are performing optimally. Understanding how load average is calculated is a crucial part of managing a Linux system effectively. In this article, we will explore how the load average is calculated in Linux and what factors contribute to its value.

What is Load Average?

Before we go into how load average is calculated, it is essential to understand what it is. Load average is a measure of the average amount of work that a CPU is doing over a specified period of time. It is calculated as the sum of the number of processes that are either in a running or uninterruptible sleep state. The load average is usually a three-digit number, with the first digit indicating the load average over the last minute, the second digit indicating the load average over the last five minutes, and the third digit indicating the load average over the last 15 minutes.

How is Load Average Calculated?

The load average is calculated by the kernel of the Linux operating system, based on the number of processes that are either running or in an uninterruptible sleep state. When a process is running, it is using the CPU, and its presence is reflected in the load average. The load average is incremented by one for every process that is running or in the uninterruptible sleep state. When a process goes into the running state, the load average is incremented by one. When a process goes into the uninterruptible sleep state, it is still using the CPU, but it is waiting for a resource to become available, such as disk or network I/O. The load average is incremented by one for every process that is in the uninterruptible sleep state.

Factors Affecting Load Average

Several factors contribute to the load average, including the number of running processes, the number of CPU cores, and the workload of the processes running on the system. If there are more processes running on the system, the load average will increase, because the CPU has to work harder to execute all the processes. If there are more CPU cores, the load average may be lower because there is more processing power available to handle the workload. The workload of the processes running on the system is also a factor that affects the load average. Processes that are more CPU-intensive will contribute more to the load average than processes that are less CPU-intensive.

Conclusion

In conclusion, load average is an essential metric that system administrators use to monitor the performance of their Linux servers. The load average is calculated by the kernel based on the number of processes that are either running or in the uninterruptible sleep state. Several factors contribute to the load average, including the number of running processes, the number of CPU cores, and the workload of the processes running on the system. Understanding how load average is calculated is crucial to managing a Linux system effectively, and is an essential concept for any aspiring Linux system administrator to learn.