通过sysinfo获取Linux系统状态信息

  系统运行状态信息是我们关注的重点，通过当前系统的输出信息，如内存大小、进程数量、运行时间等，以便分析CPU负载、软硬件资源占用情况，确保系统高效和稳定。Linux系统中，提供sysinfo以获取相关运行状态信息。

• sysinfo调用原型

#include <sys/sysinfo.h>
int sysinfo(struct sysinfo *info);

  形参，info，返回状态信息
  返回，成功反0，失败返回-1，错误码存于error中

• 具体看看struct sysinfo数据结构

struct sysinfo {  
      long uptime;          /* 系统运行时间 */  
      unsigned long loads[3];/* 平均负载，与top命令查看的类似 */    
      /* 1, 5, and 15 minute load averages */  
      unsigned long totalram;  /* 总内存 */  
      unsigned long freeram;   /* 空闲内存 */  
      unsigned long sharedram; /* 共享内存 */  
      unsigned long bufferram; /* 缓冲区*/  
      unsigned long totalswap; /* 交换区大小 */  
      unsigned long freeswap;  /* 空闲交换分区*/  
      unsigned short procs;    /* 进程数目 */  
      unsigned long totalhigh; /* 总内存高位 */  
      unsigned long freehigh;  /* 空闲内存高位 */  
      unsigned int mem_unit;   /* 以字节为单位的内存大小 */  
      char _f[20-2*sizeof(long)-sizeof(int)];   /* 保留空间 */
};  

• sysinfo用法

  可以通过万能“男人”man查看其用法。

acuity@ubuntu:~$ man sysinfo
SYSINFO(2)                                                                                           Linux Programmer's Manual                                                                                           SYSINFO(2)

NAME
       sysinfo - returns information on overall system statistics

SYNOPSIS
       #include <sys/sysinfo.h>

       int sysinfo(struct sysinfo *info);

DESCRIPTION
       Until Linux 2.3.16, sysinfo() used to return information in the following structure:

           struct sysinfo {
               long uptime;             /* Seconds since boot */
               unsigned long loads[3];  /* 1, 5, and 15 minute load averages */
               unsigned long totalram;  /* Total usable main memory size */
               unsigned long freeram;   /* Available memory size */
               unsigned long sharedram; /* Amount of shared memory */
               unsigned long bufferram; /* Memory used by buffers */
               unsigned long totalswap; /* Total swap space size */
               unsigned long freeswap;  /* swap space still available */
               unsigned short procs;    /* Number of current processes */
               char _f[22];             /* Pads structure to 64 bytes */
           };

       and the sizes were given in bytes.

       Since Linux 2.3.23 (i386), 2.3.48 (all architectures) the structure is:

           struct sysinfo {
               long uptime;             /* Seconds since boot */
               unsigned long loads[3];  /* 1, 5, and 15 minute load averages */
               unsigned long totalram;  /* Total usable main memory size */
               unsigned long freeram;   /* Available memory size */
               unsigned long sharedram; /* Amount of shared memory */
               unsigned long bufferram; /* Memory used by buffers */
               unsigned long totalswap; /* Total swap space size */
               unsigned long freeswap;  /* swap space still available */
               unsigned short procs;    /* Number of current processes */
               unsigned long totalhigh; /* Total high memory size */
               unsigned long freehigh;  /* Available high memory size */
               unsigned int mem_unit;   /* Memory unit size in bytes */
               char _f[20-2*sizeof(long)-sizeof(int)]; /* Padding to 64 bytes */
           };

       and the sizes are given as multiples of mem_unit bytes.

• 来个具体例子

#include <stdio.h>
#include <sys/sysinfo.h>
 
int main(int argc,char **argv)
{
    struct sysinfo sys_info;
    
    if (sysinfo(&sys_info))
    {
        perror("call sysinfo failed\n");
        return -1;
    }
    
    printf("running time: %lu S\n", sys_info.uptime);
    printf("1 minute load average : %lu\n", sys_info.loads[0]);    
    printf("5 minute load average : %lu\n", sys_info.loads[1]);    
    printf("15 minute load average: %lu\n", sys_info.loads[2]);

    printf("total memory: %lu MB\n", sys_info.totalram/1024/1024);
    printf("free memory: %lu MB\n", sys_info.freeram/1024/1024);
    printf("swap total memory: %lu MB\n", sys_info.totalswap/1024/1024);
    printf("swap free memory: %lu MB\n", sys_info.freeswap/1024/1024);
    printf("running progress: %u\n", sys_info.procs);    
    
    return 0;
}

• 实例运行结果

acuity@ubuntu:/home$ gcc sysinfo.c -o sysinfo
acuity@ubuntu:/home$ ./sysinfo
running time: 13856 S
1 minute load average : 4032
5 minute load average : 992
15 minute load average: 256
total memory: 7965 MB
free memory: 6163 MB
swap total memory: 0 MB
swap free memory: 0 MB
running progress: 452