Golang language is generally considered efficient, but in some cases, its CPU usage does not reach 100% even under heavy load. This article will discuss this problem and provide some solutions.
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Golang is a very popular programming language known for its efficiency, simplicity and ease of use. Many people use Golang to develop high-performance applications because it can easily handle high concurrent requests. However, in an application I wrote using Golang, I discovered an issue: Golang was not able to use 100% of the CPU in certain situations.
Why can't Golang use 100% CPU?
When dealing with high loads, we want our applications to use the CPU as much as possible for maximum performance. However, Golang programs cannot use 100% of the CPU even under heavy load. Why is this?
This is because Golang runtime dynamically adjusts CPU usage. In other words, Golang will dynamically adjust the CPU usage while the program is running. This adjustment is based on runtime conditions, that is, Golang will adaptively adjust CPU usage based on the current load situation. This seems like a good way to go about it, but it will impose some limitations on our application.
Because the Golang runtime dynamically adjusts the CPU usage, it will not always use 100% of the CPU even under high load conditions. This results in when we need to use the CPU as much as possible, we are unable to do so.
How to make Golang use 100% of the CPU?
Since Golang’s runtime dynamically adjusts CPU usage, how do we make Golang use 100% of the CPU? There are several methods you can try:
Golang’s runtime.GOMAXPROCS() method allows us to set the program runtime. Number of CPU cores used. If we want the program to use 100% of the CPU, we can set it to the number of cores of the CPU as follows:
package main import ( "fmt" "runtime" ) func main() { numCPU := runtime.NumCPU() fmt.Println(numCPU) runtime.GOMAXPROCS(numCPU) // rest of the code }
This will allow the runtime to use all available CPU cores, thus making the program use 100 % of CPU.
The Golang runtime uses a concurrency mechanism called "goroutines" (lightweight threads). The runtime.LockOSThread() method prevents the Go runtime from stopping the current thread's CPU usage when switching goroutines. If we want the program to use the current thread's CPU, we can use the following code:
package main import ( "fmt" "runtime" ) func main() { numCPU := runtime.NumCPU() fmt.Println(numCPU) runtime.GOMAXPROCS(numCPU) runtime.LockOSThread() // rest of the code }
This will prevent the Golang runtime from stopping the current thread's CPU usage when switching goroutines, so the program will use 100% of the current thread's CPU .
Another method is to use the syscall.Setpriority() method, which sets the CPU priority of the process. We can make the process use 100% of the CPU by setting the priority to the highest level, as shown below:
package main import ( "fmt" "runtime" "syscall" ) func main() { numCPU := runtime.NumCPU() fmt.Println(numCPU) runtime.GOMAXPROCS(numCPU) if err := syscall.Setpriority(syscall.PRIO_PROCESS, 0, -20); err != nil { fmt.Println("Error setting priority") } // rest of the code }
This will make the process use the highest CPU priority, thus using 100% of the CPU.
Conclusion:
When dealing with high loads, we want our applications to use the CPU as much as possible to get maximum performance. However, in an application written in Golang, we found that it was not able to use 100% of the CPU. This is because the Golang runtime's CPU usage is dynamically adjusted.
In order to let the Golang program use 100% of the CPU, we can use the runtime.GOMAXPROCS() method, as well as the runtime.LockOSThread() and syscall.Setpriority() methods. These methods allow the program to use all available CPU cores and the process to use the highest CPU priority, resulting in maximum performance.
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