Fixing Incomplete ModelName In Gopsutil Cpu.Info()

Dec 3, 2025 by Alex Johnson 51 views

This article addresses a common issue encountered when using the gopsutil library in Go to retrieve CPU information, specifically the ModelName obtained via cpu.Info(). Users have reported that the ModelName returned is sometimes incomplete compared to the output of the lscpu command on Linux systems. This can lead to inaccurate or misleading information about the CPU. We'll explore the cause of this problem and provide steps to diagnose and potentially resolve it.

The Bug: Incomplete ModelName from `cpu.Info()`

The core issue is that the cpuInfos[0].ModelName obtained using gopsutil's cpu.Info() function may not provide the complete CPU model name as displayed by the lscpu command. This discrepancy can be problematic for applications that rely on accurate CPU identification. To illustrate, consider the following scenario:

Reproduction Steps

To reproduce the bug, you can use the following Go code snippet:

import (
	"fmt"

	"github.com/shirou/gopsutil/v4/cpu"
)

func main() {
	cpuInfos, err := cpu.Info()
	if err != nil {
		fmt.Println("Error getting CPU info:", err)
		return
	}
	fmt.Println(cpuInfos[0].ModelName)
}

This code imports the necessary gopsutil package, retrieves CPU information using cpu.Info(), and prints the ModelName of the first CPU. When running this code, the output might be an incomplete model name.

Expected Behavior

The expected behavior is that the output of the Go program should match the Model name field displayed by the lscpu command. For example, if lscpu shows:

# lscpu
...
Model name:                         Hygon C86-4G (OPN:5435)
BIOS Model name:                    Hygon C86-4G (OPN:5435)
...

the Go program should output the same full name: Hygon C86-4G (OPN:5435). However, the actual output might be truncated, such as Hygon C86-4G (OPN.

Environment

This issue has been observed on Linux systems, specifically on Kylin Linux Advanced Server V10 (Halberd). The kernel version is 4.19.90-89.25.v2401.ky10.x86_64. This suggests that the problem might be related to how gopsutil reads CPU information on certain Linux distributions or kernel versions. It's important to test on different environments to identify any patterns or specific conditions that trigger the bug.

Example

Consider the following output from lscpu:

# lscpu
......
Model name:                         Hygon C86-4G (OPN:5435)
BIOS Model name:                    Hygon C86-4G (OPN:5435)
......

But the cpuInfos[0].ModelName output is:

Hygon C86-4G (OPN

This discrepancy indicates a problem in how gopsutil is parsing the CPU model name.

Root Cause Analysis

The likely cause of this issue is related to the parsing of the /proc/cpuinfo file, which is the primary source of CPU information on Linux systems. gopsutil reads this file to gather details about the CPU, including the model name. The problem arises when the model name contains special characters, such as colons (:) or spaces, which might not be handled correctly by the parsing logic.

In the provided example, the Model name in /proc/cpuinfo likely contains a colon. The parsing logic in gopsutil might be truncating the string at the colon, resulting in an incomplete model name. To confirm this, you can examine the /proc/cpuinfo file on the affected system and look for the model name field.

Investigating `/proc/cpuinfo`

To inspect the contents of /proc/cpuinfo, use the following command:

cat /proc/cpuinfo

Look for the model name field for each CPU core. For example:

processor	: 0
vendor_id	: AuthenticAMD
cpu family	: 23
model		: 113
model name	: Hygon C86-4G (OPN:5435)
stepping	: 0
microcode	: 0x100012c
cpu MHz		: 2000.000
cache size	: 512 KB
physical id	: 0
siblings	: 8
core id		: 0
cpu cores	: 8
apicid		: 0
initial apicid	: 0
fpu		: yes
fpu_exception	: yes
cpuid level	: 13
wp		: yes
vme		: yes
pcmci		: yes
tscp		: yes
...

If the model name field in /proc/cpuinfo matches the full name displayed by lscpu, but gopsutil returns an incomplete name, it confirms that the parsing logic is the issue.

Possible Solutions and Workarounds

Several approaches can be taken to address this issue, ranging from temporary workarounds to more permanent solutions.

1. String Manipulation

A simple workaround is to manually process the ModelName string obtained from gopsutil. You can use string manipulation functions in Go to extract the complete model name. For example, if you know that the truncation occurs at a specific character (like a colon), you can search for that character and extract the substring before it.

However, this approach is not ideal as it relies on specific knowledge of the truncation pattern and might not work in all cases. It's more of a temporary fix rather than a robust solution.

import (
	"fmt"
	"strings"

	"github.com/shirou/gopsutil/v4/cpu"
)

func main() {
	cpuInfos, err := cpu.Info()
	if err != nil {
		fmt.Println("Error getting CPU info:", err)
		return
	}

	modelName := cpuInfos[0].ModelName
	// Check if the model name is truncated at the colon
	if strings.Contains(modelName, ":") {
		// Extract the substring before the colon
		modelName = strings.Split(modelName, ":")[0]
	}

	fmt.Println(modelName)
}

2. Direct Parsing of `/proc/cpuinfo`

Another workaround is to bypass gopsutil's cpu.Info() function and directly parse the /proc/cpuinfo file. This gives you more control over the parsing logic and allows you to handle special characters and formatting issues as needed. While this approach can provide a more accurate result, it also requires more code and effort.

import (
	"bufio"
	"fmt"
	"os"
	"strings"
)

func getModelName() (string, error) {
	file, err := os.Open("/proc/cpuinfo")
	if err != nil {
		return "", err
	}
	defer file.Close()

	scanner := bufio.NewScanner(file)
	for scanner.Scan() {
		line := scanner.Text()
		if strings.HasPrefix(line, "model name") {
			parts := strings.SplitN(line, ":", 2)
			if len(parts) > 1 {
				return strings.TrimSpace(parts[1]), nil
			}
		}
	}
	if err := scanner.Err(); err != nil {
		return "", err
	}
	return "", fmt.Errorf("model name not found in /proc/cpuinfo")
}

func main() {
	modelName, err := getModelName()
	if err != nil {
		fmt.Println("Error getting model name:", err)
		return
	}
	fmt.Println(modelName)
}

3. Filing a Bug Report and Contributing to `gopsutil`

The most effective long-term solution is to report the bug to the gopsutil project and contribute a fix. This ensures that the library correctly handles CPU model names in future versions. To do this:

Create an Issue: Open a new issue on the gopsutil GitHub repository (https://github.com/shirou/gopsutil). Provide detailed information about the bug, including the steps to reproduce it, the expected behavior, and the actual behavior. Include the relevant environment details, such as the Linux distribution, kernel version, and lscpu output.
Contribute a Fix: If you are familiar with Go and have identified the parsing logic that causes the issue, you can submit a pull request with a fix. This involves modifying the gopsutil code to correctly handle special characters and formatting in the /proc/cpuinfo file.

4. Using Alternative Libraries

If the issue persists and a timely resolution is critical, consider exploring alternative libraries for retrieving system information in Go. While gopsutil is a popular choice, other libraries might offer better compatibility or more robust parsing logic for certain systems.

Conclusion

The problem of incomplete ModelName retrieval using gopsutil's cpu.Info() function can be frustrating, but understanding the root cause and available solutions can help mitigate the issue. By examining /proc/cpuinfo, implementing workarounds, and contributing to the gopsutil project, you can ensure accurate CPU information retrieval in your Go applications. Remember to always test your solutions thoroughly and report any issues you encounter to help improve the library for everyone.

For more information on system monitoring and Go, visit the official Go website and relevant documentation. You can also explore other system information libraries in Go to find the best fit for your needs. Consider checking out resources like the Sysinfo library as an alternative. This article aimed to explain why the ModelName from cpu.Info() might be incomplete and how to address the problem effectively.