This post explains CPU load, how it affects your Linux server, and how to deal with it in critical moments. We think about high CPU usage and CPU load when discussing essential moments. These are two different things, even though they sound similar. Besides this, we will explain the CPU as the most critical part of a server. What causes high CPU utilization, different commands to check the CPU utilization, and some suggestions to prevent high usage
In other words, how to manage your CPU resources rationally so your hosted websites are free of issues. Let’s get started!
Table of Contents
What is CPU?
The central processor unit (CPU) is like the brain of a computer or server, executing a computer program’s instructions. All of the system’s major components, such as RAM, storage, and graphics, rely on instructions from the CPU. Every CPU has dedicated CPU cores and threads, essential components that can significantly impact its overall performance. A CPU core is a physical unit that can execute instructions independently. Conversely, a thread is a logical software unit that can run on a single core. There are single-core and multi-core processors. In a single-core processor, the CPU can handle only one task at a time. A multi-core processor CPU can handle multiple tasks independently of each of its tasks.
What is CPU Load?
The CPU Load refers to the number of tasks waiting for CPU time. Typically, CPU load is represented as load averages over 1-minute, 5-minute, and 15-minute averages. A high CPU load is when the tasks compete for processing resources, leading to slower responsiveness and performance. An idle processor has a load of 0.0, but the load average depends on how many threads the CPU boasts.
For example, a server with two physical CPUs, each with four CPU cores, has eight cores. With eight cores, we have an average CPU load of 8. Anything less than eight will put the server under capacity. Conversely, anything over eight will put the processes in the queue (over capacity). Additional process requests will be queued if the load exceeds the number of CPU cores.
The Linux operating system makes no distinction between multi-core and multi-processor systems. In our case, two processors with four cores each are considered a single CPU with eight logical cores. High CPU loads can result from many factors, including intensive complex tasks, too many simultaneous tasks, stuck processes, etc.
What is CPU Usage?
CPU usage or utilization measures the percentage of time the CPU spends actively processing tasks. High CPU usage indicates that the CPU executes instructions and processes data. It is a proportion of the total available processor cycles consumed by each process. However, high CPU usage does not overload the system if the tasks are efficiently managed. There are many reasons for high CPU usage, such as background processes, malware, data encryption, outdated software, etc.
How to Monitor CPU Load?
A couple of commands can be used to check and monitor the CPU load. The first command is the uptime. Let’s execute this command on the command line:
uptime
You should get output similar to this:
root@host:~# uptime 17:46:54 up 46 days, 9:36, 2 users, load average: 0.08, 0.02, 0.00
The command above displays the time our system has been up, the active users, and the load average. As you can see, the load average is 0.08 for the last minute, 0.02 for the last five, and 0.00 for the last 15 minutes.
The next command that we can use is the htop command. It can be installed with the following commands depending on the Linux OS:
sudo apt get install htop -y #Debian based OS distribution sudo yum install htop -y #RHEL based OS distribution
Execute the htop command on the command line will give you output similar to this:
/Image1
As you can see, the load average is the same 0.00 for the last minute, last five minutes, and last 15 minutes.
Another simple command to check the load average is the cat /proc/loadavg command:
root@host:~# cat /proc/loadavg 0.00 0.00 0.00 1/263 535132
Other tools you can install to monitor the load average include Glances, Cacti, Nagios, Prometheus, Icinga, and many more, with great graphical interfaces and other features.
How to Manage the CPU Load?
Under management, the CPU load is kept in check to improve performance and extend the life of the server hardware. To improve the performance, we need to reduce the CPU load by identifying which processes consume most of the CPU and terminating them immediately. If those processes are important for your website, you need to restart those processes. Check the background processes, if there are any, and kill them immediately. They were running in the background even though you stopped them previously. The startup processes can also be checked. Many processes start after a server reboot, which you do not need.
The software on your server must always be up to date, so you need to update the system packages to their latest versions periodically. Scanning the server for malware is always a good idea. Sometimes, malicious scripts may be uploaded to your server for crypto mining or other malicious actions. Optimizing the application code and database queries is also a good idea.
If everything is OK with your server and the CPU load is still high, then it is time to upgrade or split the server resources. This means that your current server plan is not enough and can not handle the traffic that comes to your website. If you are using a powerful plan and the CPU load is high, then you need to split the database server to another powerful server as well.
Conclusion
There are no strict rules for reducing CPU load, which cannot always be managed easily. This is a process that you need to approach holistically.
You learned some basic information about the CPU load and how to reduce it if necessary. Of course, you do not need to do it by yourself if you are not familiar with Linux, but want to host a website. All you have to do is sign up for one of our NVMe VPS plans and submit a support ticket. We are available 24/7 via live chat and ticketing system. We will help you with any aspect of your website and make sure the load is stable.
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