http://www.blogjava.net/fjzag/articles/317773.html

ubuntu@ubuntu-vm:/work/sv-g5-application/projects/sysmonitor/src$ cat SVPSysMonitor.cpp 
/*##################################################################################################

    Company       : Huizhou Desay SV Automotive Co., Ltd.

    Division      : Automotive Electronics, Desay Corporation

    Business Unit : Central Technology

    Department    : Advanced Development (Huizhou)

    Project       : G5 Platform

    Module        : System Monitor

    Create Date   : Nov 03, 2016 - Liu Chuqun <Chuqun.Liu@desay-svautomotive.com>

    Update Date   :

##################################################################################################*/

#include "SVPType.h"
#include "SVPTime.h"
#include "SVPLog.h"

#ifdef SVP_LOG_TAG
    #undef SVP_LOG_TAG
#endif
#define SVP_LOG_TAG     "sysmonitor"

#define NAME_LEN 64
#define BUFFER_LEN 1024

static SVPChar g_name[NAME_LEN] = { 0 };
static SVPChar g_buffer[BUFFER_LEN] = { 0 };
static SVPInt32 g_cpuPercent = 0;
static SVPInt32 g_memPercent = 0;
static SVPInt32 g_memTotal = 0;
static SVPInt32 g_memFree = 0;
static SVPInt32 g_memAvailable = 0;
static SVPInt32 g_topCPU = 0;
static SVPInt32 g_topMemUse = 0;

void GetCPUInfo();
void GetMemInfo();
void PrintInfo();
void MonitorStrategy();
SVPVoid ResetSystem();

SVPInt32 main(SVPInt32 argc, SVPChar* argv[])
{
    while(1)
    {
        GetCPUInfo();
        GetMemInfo();
        PrintInfo();
        MonitorStrategy();
        sleep(3);
    }

    return 0;
}

void MonitorStrategy()
{
    SVPUlong ulCurStrategyTickCount = SVPTime::GetTickCount();
    if (ulCurStrategyTickCount <= 30000)
        return;// 开机30秒内不执行策略。

    static SVPBool s_bInLimitMode = SVP_FALSE;
    static SVPUlong s_ulEnterLimitModeTime = 0;
    static SVPUlong s_ulLimitModeCheckCount = 0;
    if (g_cpuPercent >= 100)
    {
        ++s_ulLimitModeCheckCount;
        if (SVP_FALSE == s_bInLimitMode)
        {
            s_bInLimitMode = SVP_TRUE;
            s_ulEnterLimitModeTime = ulCurStrategyTickCount;
        }

        if (ulCurStrategyTickCount - s_ulEnterLimitModeTime >= 90000)
        {
            SVP_INFO("s_ulLimitModeCheckCount[%lu]", s_ulLimitModeCheckCount);
            if (s_ulLimitModeCheckCount >= 30)
                ResetSystem();
        }
    }
    else
    {
        s_bInLimitMode = SVP_FALSE;
        s_ulLimitModeCheckCount = 0;
    }
}

void PrintInfo()
{
    SVP_INFO("[TopMem:%3d%%, TopCPU:%3d%%] MemTotal:%dKB, MemAvailable:%dKB, MEM:%3d%%, CPU:%3d%%.", g_topMemUse, g_topCPU, g_memTotal, g_memAvailable, g_memPercent, g_cpuPercent);
    static SVPInt32 printCount = 0;
    ++printCount;
    if (printCount >= 60)
    {
        printCount = 0;
        system("ps");
        usleep(100000);
        system("top -n1;ls /media");
    }
}

void GetCPUInfo()
{//获取cpu占用率
    FILE *fp = fopen("/proc/stat", "r");
    if (fp)
    {
        memset(g_name, 0, NAME_LEN);
        memset(g_buffer, 0, BUFFER_LEN);
        static SVPInt32 idle0 = 0, total0 = 0;
        SVPInt32 user1, nice, sys, idle1, iowait, irq, softirq, total1 = 0;

        fgets(g_buffer, sizeof(g_buffer), fp);
        sscanf(g_buffer, "%s %d %d %d %d %d %d %d", g_name, &user1, &nice, &sys,
                &idle1, &iowait, &irq, &softirq);

        total1 = user1 + nice + sys + iowait + irq + softirq + idle1;
        if (total1 != total0)
             g_cpuPercent = 100 - ( ((idle1 - idle0) * 100)/ (double) (total1 - total0) );
        else
            SVP_WARN("cpu total is the same. /proc/stat maybe error!");

        idle0 = idle1;
        total0 = total1;

        if (g_cpuPercent > g_topCPU)
            g_topCPU = g_cpuPercent;

        fclose(fp);
    }
    else
    {
        SVP_ERROR("fopen /proc/stat failed:%s", strerror(errno));
    }
}

void GetMemInfo()
{//获取内存信息
    FILE *fp = fopen("/proc/meminfo", "r");
    if (fp)
    {
        memset(g_name, 0, NAME_LEN);
        memset(g_buffer, 0, BUFFER_LEN);
        SVPChar unit[10] = { 0 };
        fgets(g_buffer, sizeof(g_buffer), fp);
        sscanf(g_buffer, "%s %d %s", g_name, &g_memTotal, unit);

        fgets(g_buffer, sizeof(g_buffer), fp);
        sscanf(g_buffer, "%s %d %s", g_name, &g_memFree, unit);

        fgets(g_buffer, sizeof(g_buffer), fp);
        sscanf(g_buffer, "%s %d %s", g_name, &g_memAvailable, unit);

        if (g_memTotal)
            g_memPercent = 100 - (100 * g_memAvailable) / g_memTotal;
        else
            SVP_WARN("mem total is 0!");

        if (g_memPercent > g_topMemUse)
            g_topMemUse = g_memPercent;

        fclose(fp);
    }
    else
    {
        SVP_ERROR("fopen /proc/meminfo failed:%s", strerror(errno));
    }
}

SVPVoid ResetSystem()
{
    system("top -n1;ls /media");
    SVP_WARN("restart system now ...");
    SVPUint8 tryTimes = 0;
    while(tryTimes < 3)
    {
        ++tryTimes;
        if (-1 != system("powerctrl 10 &"))
            break;
        else
            SVP_ERROR("reboot system fail!");
        sleep(1);
    }

    //最后一招。
    //需要radio软件修改逻辑为：任何时候，只要收到first connect消息，就走core重新启动的逻辑。不要再过滤first connect消息。
    sleep(5);
    SVP_ERROR("can‘t restart system through the spi msg!");
    tryTimes = 0;
    while(tryTimes < 3)
    {
        ++tryTimes;
        if (-1 != system("reboot -f &"))
            break;
        else
            SVP_ERROR("reboot system fail!");
        sleep(1);
    }
}