cpp-linux-system-stats

Single-header, straight-forward API to read CPU, Memory, thermal zone temperature & Disk usage for linux systems. The data are extracted respectively from /proc/stat, /proc/meminfo and statvfs.

Example

#include <chrono>
#include <thread>
#include "linux-system-usage.hpp"

using namespace get_system_usage_linux;

int main() {
    
    // CPU usage
    CPU_stats t1 = read_cpu_data();

    std::this_thread::sleep_for(std::chrono::milliseconds(1000));

    CPU_stats t2 = read_cpu_data();

    std::cout << "CPU usage is " << (100.0f * get_cpu_usage(t1, t2)) << "%\n";
    
    //see https://unix.stackexchange.com/questions/304845/discrepancy-between-number-of-cores-and-thermal-zones-in-sys-class-thermal/342023 to realize the correct index for your CPU
    const int cpu_thermal_zone = 2;
    int cpu_temp = get_thermalzone_temperature(cpu_thermal_zone);
    
    std::cout << "CPU temperature is " << (cpu_temp / 1000) << "°C\n";

    // Memory usage
    auto memory_data = read_memory_data();

    std::cout << "Swap usage is " << (100.0f * memory_data.get_swap_usage()) << "%\n";

    std::cout << "Memory usage is " << (100.0f * memory_data.get_memory_usage()) << "%\n";

    // Disk usage
    std::cout << "Disk usage is " << (100.0f * get_disk_usage("/")) << "%\n";

}

Expected output:

$ c++ -Iinclude main.cpp
$ ./a.out 
CPU usage is 35.9199%
CPU temperature is 42°C
Swap usage is 31.189%
Memory usage is 79.6201%
Disk usage is 67.2953%
$

Why do not use sysinfo to get memory consume?

One way to obtain memory usage is via sysinfo as follows:

struct sysinfo memory_info;
sysinfo (&memory_info);
long long mem_used = memory_info.totalram - memory_info.freeram;

The problem with this approach is that freeram represents the real amount of non-allocated memory. It turns out that linux systems cache lots of memory ram which is actually available to be used for any process. However, this cached memory is considered by sysinfo as non-free memory. Since there is no way to measure the cached memory using only sysinfo I ended up by extracting memory usage from /proc/meminfo. For more information about sysinfo see: https://man7.org/linux/man-pages/man2/sysinfo.2.html