linux下计算pod的cpu利用率与mem使用情况

一、计算CPU利用率（计算方式与top指令源码方式相同）

1.计算宿主机的cpu核数

2. 从文件中读取本身进程的一段时间使用情况，即隔一段时间分别获取使用情况，通过这段时间的（使用时间）/（总时间），即可得到cpu利用率，代码如下：

 

#include "stdlib.h"
#include "stdio.h"
#include "unistd.h"
#include <iostream>
#include <string>
#include <fstream>

typedef struct cpu_usage_info
{
    unsigned long cpu_total_usage;
    unsigned long system_useage;
}CPU_USAGE_INFO;

typedef struct cpu_sys_info
{
    char szName[16];
    unsigned long user; // 从系统启动开始累计到当前时刻，用户态的CPU时间（单位：jiffies） ，不包含 nice值为负进程。1jiffies=0.01秒
    unsigned long nice; // 从系统启动开始累计到当前时刻，nice值为负的进程所占用的CPU时间（单位：jiffies）
    unsigned long system; // 从系统启动开始累计到当前时刻，核心时间（单位：jiffies）
    unsigned long idle; // 从系统启动开始累计到当前时刻，除硬盘IO等待时间以外其它等待时间（单位：jiffies）
    unsigned long iowait; // 从系统启动开始累计到当前时刻，硬盘IO等待时间（单位：jiffies） ，
    unsigned long irq; // 从系统启动开始累计到当前时刻，硬中断时间（单位：jiffies）
    unsigned long softirq; // 从系统启动开始累计到当前时刻，软中断时间（单位：jiffies）
}CPU_SYS_INFO;

long GetCpuNum()
{
    std::fstream fIn("/proc/stat", std::ios::in);
    if(false == fIn.is_open())
    {
        return -1;
    }
    std::string strLine1;
    std::string strLineCpu; // 含有CPU字段的文本
    do
    {
        std::getline(fIn, strLine1);
        auto nPos = strLine1.find("cpu");
        // 本行文本不包含cpu字段则跳出
        if(std::string::npos == nPos)
        {
            break;
        }
        else{
            // 本行包含cpu字段则保存起来
            strLineCpu = strLine1;
        }
    }
    while(!fIn.eof());
    if(true == strLineCpu.empty())
    {
        std::cout << "get cpu num failed." << std::endl;
        return -1;
    }
    else{
        auto nPos = strLineCpu.find(" ");
        std::string strCpu = strLineCpu.substr(3, nPos-3);
        //std::cout << "--------" << strCpu << std::endl;
        long lCpuNum = atoi(strCpu.c_str()) + 1;
        //std::cout << "CpuNum: " << lCpuNum << std::endl;
        return lCpuNum;
    }
    
}

long getCPUInfo(CPU_USAGE_INFO *pstCpuUsageInfo)
{
    // 读取CPU使用时间，单位纳秒
    char szCpuAcctUsagePath[256] = "/sys/fs/cgroup/cpuacct/cpuacct.usage";
    char szBuff[256];
    FILE* fd;
    fd = fopen(szCpuAcctUsagePath,"r");
    if(NULL == fd)
    {
        printf("open file cpuacct.usage failed.");
        return -1;
    }
    fgets(szBuff, sizeof(szBuff),fd);

    sscanf(szBuff,"%lu",&pstCpuUsageInfo->cpu_total_usage);

    fclose(fd);
    fd = NULL;
    
    // 读取系统CPU使用时间，单位jiffies（0.01s）
    CPU_SYS_INFO stCpuSysInfo;
    char szCpuSystemUsagePath[256] = "/proc/stat";
    fd = fopen(szCpuSystemUsagePath,"r");
    if(NULL == fd)
    {
        printf("open file stat failed.");
        return -1;
    }
    fgets(szBuff, sizeof(szBuff), fd);

    sscanf(szBuff, "%s %lu %lu %lu %lu %lu %lu %lu", 
    stCpuSysInfo.szName, &stCpuSysInfo.user, &stCpuSysInfo.nice, &stCpuSysInfo.system, &stCpuSysInfo.idle, 
    &stCpuSysInfo.iowait, &stCpuSysInfo.irq, &stCpuSysInfo.softirq);
    
    pstCpuUsageInfo->system_useage = stCpuSysInfo.user+stCpuSysInfo.nice+stCpuSysInfo.system+
    stCpuSysInfo.idle+stCpuSysInfo.iowait+ stCpuSysInfo.irq+ stCpuSysInfo.softirq;
    fclose(fd);
    return 0;
}

long getCpuRate()
{
    
    
    CPU_USAGE_INFO stPreCpuUsageInfo;
    CPU_USAGE_INFO stCpuUsageInfo;
    
    long lRet = -1;
    lRet = getCPUInfo(&stPreCpuUsageInfo);
    if(0 != lRet)
    {
        printf("get PreCpuUsage failed.\n");
        return -1;
    }
    
    // 等待200ms
    usleep(200000);
    //sleep(1);
    lRet = getCPUInfo(&stCpuUsageInfo);
    if(0 != lRet)
    {
        printf("get CpuUsage failed.\n");
        return -1;
    }
/*     printf("Usage:%lu, %lu;\n", stCpuUsageInfo.cpu_total_usage, stPreCpuUsageInfo.cpu_total_usage);
    printf("Sys:%lu,%lu\n", stCpuUsageInfo.system_useage,stPreCpuUsageInfo.system_useage);
    printf("cpu delta:%lu\n", (stCpuUsageInfo.cpu_total_usage- stPreCpuUsageInfo.cpu_total_usage));
    printf("sys delta:%lu\n", stCpuUsageInfo.system_useage-stPreCpuUsageInfo.system_useage); */
    // 
    float fCpuRate = (float)(stCpuUsageInfo.cpu_total_usage- stPreCpuUsageInfo.cpu_total_usage)/(float)((stCpuUsageInfo.system_useage-stPreCpuUsageInfo.system_useage)*100000);
    long lCpuNum = GetCpuNum();
    printf("Using Cpu rate:%f\n", fCpuRate*lCpuNum);
    return (long)fCpuRate;
    //return 0;
}

int main()
{
    std::cout << "system Cpu Number: " <<GetCpuNum() << std::endl;
    while(true)
    {
        long lRet = getCpuRate();
        sleep(1);
        std::cout << std::endl;
    }
    return 0;
}

如果想获取本身的使用情况，需要获取pid，进入对应的文件夹下读取信息，百度一下就知道；

附送C版本getNum

long GetCpuNum()
{
    char szBuff[1024];
    char szLine[1024];
    char *szCpuNum = NULL;
    FILE *fIn = fopen("/proc/stat", "r");
    if(NULL == fIn)
    {
        printf("open /proc/stat failed, error getting cpu num\n");
        return -1;
    }
    while(fgets(szBuff, sizeof(szBuff), fIn) != NULL)
    {
        printf("%s\n", szBuff);
        char *s = strstr(szBuff,"cpu");
        if(NULL == s)
        {
            break;
        }
        else
        {
            strncpy(szLine, szBuff, sizeof(szLine)-1);
        }
    }
    if(strlen(szLine) == 0)
    {
        printf("get cpu line failed\n");
        return -1;
    }
    else
    {
        printf("\n");
        printf("szLine:%s", szLine);
        szCpuNum = strtok(szLine, " ");
        printf("cpuNum:%d\n", atoi(szCpuNum+3));
        return (long)atoi(szCpuNum);
    }
}

二、获取mem使用情况

未完待续