linux c程序获取cpu使用率及内存使用情况-蒲公英云

想获取一下目标机运行时linux系统的硬件占用情况，写了这几个小程序，以后直接用了。

方法就是读取proc下的文件来获取了。 cpu使用率：    /proc/stat ，内存使用情况：      /proc/meminfo

看程序：

/*

    @file:        statusinfo.c

    @brief:        从linux系统获取cpu及内存使用情况

    @version    1.0

    @author        抹黑

    @date        2009年3月17日

*/

typedef struct PACKED         //定义一个cpu occupy的结构体

{

char name[20];      //定义一个char类型的数组名name有20个元素

unsigned int user; //定义一个无符号的int类型的user

unsigned int nice; //定义一个无符号的int类型的nice

unsigned int system;//定义一个无符号的int类型的system

unsigned int idle; //定义一个无符号的int类型的idle

}CPU_OCCUPY;

typedef struct PACKED         //定义一个mem occupy的结构体

{

char name[20];      //定义一个char类型的数组名name有20个元素

unsigned long total;

char name2[20];

unsigned long free;

}MEM_OCCUPY;

get_memoccupy (MEM_OCCUPY mem) //对无类型get函数含有一个形参结构体类弄的指针O

{

    FILE fd;

    int n;

    char buff[256];

    MEM_OCCUPY m;

    m=mem;



    fd = fopen (“/proc/meminfo”, “r”);



    fgets (buff, sizeof(buff), fd);

    fgets (buff, sizeof(buff), fd);

    fgets (buff, sizeof(buff), fd);

    fgets (buff, sizeof(buff), fd);

    sscanf (buff, “%s %u %s”, m->name, &m->total, m->name2);



    fgets (buff, sizeof(buff), fd); //从fd文件中读取长度为buff的字符串再存到起始地址为buff这个空间里

    sscanf (buff, “%s %u”, m->name2, &m->free, m->name2);



    fclose(fd);     //关闭文件fd

}

int cal_cpuoccupy (CPU_OCCUPY o, CPU_OCCUPY n)

{

    unsigned long od, nd;

    unsigned long id, sd;

    int cpu_use = 0;



    od = (unsigned long) (o->user + o->nice + o->system +o->idle);//第一次(用户+优先级+系统+空闲)的时间再赋给od

    nd = (unsigned long) (n->user + n->nice + n->system +n->idle);//第二次(用户+优先级+系统+空闲)的时间再赋给od



    id = (unsigned long) (n->user - o->user);    //用户第一次和第二次的时间之差再赋给id

    sd = (unsigned long) (n->system - o->system);//系统第一次和第二次的时间之差再赋给sd

    if((nd-od) != 0)

    cpu_use = (int)((sd+id)10000)/(nd-od); //((用户+系统)乖100)除(第一次和第二次的时间差)再赋给g_cpu_used

    else cpu_use = 0;

    //printf(“cpu: %u\n”,cpu_use);

    return cpu_use;

}

get_cpuoccupy (CPU_OCCUPY cpust) //对无类型get函数含有一个形参结构体类弄的指针O

{

    FILE fd;

    int n;

    char buff[256];

    CPU_OCCUPY cpu_occupy;

    cpu_occupy=cpust;



    fd = fopen (“/proc/stat”, “r”);

    fgets (buff, sizeof(buff), fd);



    sscanf (buff, “%s %u %u %u %u”, cpu_occupy->name, &cpu_occupy->user, &cpu_occupy->nice,&cpu_occupy->system, &cpu_occupy->idle);



    fclose(fd);

}

int main()

{

    CPU_OCCUPY cpu_stat1;

    CPU_OCCUPY cpu_stat2;

    MEM_OCCUPY mem_stat;

    int cpu;



    //获取内存

    get_memoccupy ((MEM_OCCUPY )&mem_stat);



    //第一次获取cpu使用情况

    get_cpuoccupy((CPU_OCCUPY )&cpu_stat1);

    sleep(10);



    //第二次获取cpu使用情况

    get_cpuoccupy((CPU_OCCUPY )&cpu_stat2);



    //计算cpu使用率

    cpu = cal_cpuoccupy ((CPU_OCCUPY )&cpu_stat1, (CPU_OCCUPY )&cpu_stat2);



    return 0;

}

另一参考：

http://www.cppblog.com/dyj057/archive/2007/01/31/18221.aspx

在Linux中如果要监视一个进程的运行情况，如查看它的CPU使用效率和内存使用情况，就需要从系统的/proc目录的读取一些系统信息。然后分析得到结果，特别是在嵌入式中的应用程序这个功能就很重要。本文中的代码是从top命令的源代码分析中获得，并做了部分修改，在FC6+GCC4.1调试通过。从这个工程中我也获得一些感悟。
1. Linux系统很优雅，如果在Windows中做这个功能就需要调用ActiveX控件。而在Linux中只需要读取文本。
2.想完成什么功能，如果不知道怎么做，就想有没有没有其它的软件有这个功能，如果有，查看它的源代码就可以了，然后定制自己需要的功能。
3.多想多看多做，学习技术的不二法门。

top命令源代码下载：http://www.groupsys.com/top/download.shtml
工程下载： http://www.cppblog.com/Files/dyj057/mytop.zip
源码我下载后也上传到附件中。
下面是获得系统CPU和内存情况的代码：

void

get_system_info(info)

struct  system_info
info;
{
     char  buffer[ 4096 + 1
];
     int
fd, len;
     char
p;
     int
i;

     /  get load averages  /

    {
    fd
=  open( “ loadavg “
, O_RDONLY);
    len  =  read(fd, buffer,  sizeof (buffer) - 1
);
    close(fd);
    buffer[len]  =   ‘ \0 ‘
;

    info -> load_avg[ 0 ]  =  strtod(buffer,  &
p);
    info -> load_avg[ 1 ]  =  strtod(p,  &
p);
    info -> load_avg[ 2 ]  =  strtod(p,  &
p);
    p  =  skip_token(p);             /  skip running/tasks  /

    p
=
skip_ws(p);
     if  (
p)
        info -> last_pid  =
atoi(p);
     else

        info
-> last_pid  =   - 1
;
    }

     /  get the cpu time info  /

    {
    fd
=  open( “ stat “
, O_RDONLY);
    len  =  read(fd, buffer,  sizeof (buffer) - 1
);
    close(fd);
    buffer[len]  =   ‘ \0 ‘
;

    p  =  skip_token(buffer);             /  ”cpu”  /

    cp_time[
0 ]  =  strtoul(p,  & p,  0
);

    cp_time[ 1 ]  =  strtoul(p,  & p,  0
);
    cp_time[ 2 ]  =  strtoul(p,  & p,  0
);
    cp_time[ 3 ]  =  strtoul(p,  & p,  0
);

     /  convert cp_time counts to percentages  /

    percentages(
4
, cpu_states, cp_time, cp_old, cp_diff);
    }

     /  get system wide memory usage  /

    {

char
p;

    fd  =  open( “ meminfo “
, O_RDONLY);
    len  =  read(fd, buffer,  sizeof (buffer) - 1
);
    close(fd);
    buffer[len]  =   ‘ \0 ‘
;

     /
be prepared for extra columns to appear be seeking
       to ends of lines  /


    p
=
buffer;
    p  =
skip_token(p);
    memory_stats[ 0 ]  =  strtoul(p,  & p,  10 );  /  total memory  /


    p
=  strchr(p,  ‘ \n ‘
);
    p  =
skip_token(p);
    memory_stats[ 1 ]  =  strtoul(p,  & p,  10 );  /  free memory  /



    p
=  strchr(p,  ‘ \n ‘
);
    p  =
skip_token(p);
    memory_stats[ 2 ]  =  strtoul(p,  & p,  10 );  /  buffer memory  /


    p
=  strchr(p,  ‘ \n ‘
);
    p  =
skip_token(p);
    memory_stats[ 3 ]  =  strtoul(p,  & p,  10 );  /  cached memory  /



for (i  =   0 ; i <   8  ;i ++
) {
        p ++
;
        p  =  strchr(p,  ‘ \n ‘
);
    }

    p  =
skip_token(p);
    memory_stats[ 4 ]  =  strtoul(p,  & p,  10 );  /  total swap  /


    p
=  strchr(p,  ‘ \n ‘
);
    p  =
skip_token(p);
    memory_stats[ 5 ]  =  strtoul(p,  & p,  10 );  /  free swap  /


    }


/  set arrays and strings  /

    info
-> cpustates  =
cpu_states;
    info -> memory  =
memory_stats;
}
mytop.zip