stat.c

linux性能统计的源代码

 /*
  *		File:		cpu_stat.c
  *
  *		Author:		[e-mail]
  *
  *		Date:		2009-08-25
  *
  *		Brief:		calculate the cpu usage rate
  */
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <sys/vfs.h> 
#include <sys/statvfs.h> 
#include "stat.h"

/*
 *		Function:	int cpu_stat(void)
 *		
 *		Purpose:	Statitic the cpu usage rate
 *
 *		Argument:   None
 *		
 *		Return:		Success:0	Failure:-1
 */
int cpu_stat(void)
{
	FILE *fp = NULL;
	unsigned int num = 0;
	unsigned long long idle_pre = 0, idle_next = 0;
	unsigned long long total_pre = 0, total_next = 0;
	char buf[BUFSIZE - 1] = {0}; 
	cpu_t cpu_t_next, cpu_t_pre; 
	
	fp = fopen("/proc/stat", "rb");
	if (!fp) {
		fprintf(stderr, "Unable to open /proc/stat");
		return -1;
	}
	
	if (!fgets(buf, BUFSIZE-1, fp)) {
		fclose(fp);
		return -1;	
	}
	
	memset(&cpu_t_pre, 0, sizeof(cpu_t));
	num = sscanf(buf, "cpu %lld %lld %lld %lld %lld %lld %lld %lld",
					&cpu_t_pre.user, &cpu_t_pre.nice, &cpu_t_pre.system, &cpu_t_pre.idle,
					&cpu_t_pre.iowait, &cpu_t_pre.irq, &cpu_t_pre.softirq, &cpu_t_pre.z);
	if (num >= 4) {
		idle_pre = cpu_t_pre.idle;
		total_pre = cpu_t_pre.user + cpu_t_pre.nice + cpu_t_pre.system + cpu_t_pre.idle 
		+ cpu_t_pre.iowait + cpu_t_pre.irq + cpu_t_pre.softirq + cpu_t_pre.z;
	}
	fclose(fp);
	
	sleep(1);	
	fp = fopen("/proc/stat", "rb");
	if (!fp) {
		fprintf(stderr, "Unable to open /proc/stat");
		return -1;
	}
	
	memset(buf, 0, BUFSIZE-1);
	if (!fgets(buf, BUFSIZE-1, fp)) {
		fclose(fp);
		return -1;	
	}
	
	memset(&cpu_t_next, 0, sizeof(cpu_t));
	num = sscanf(buf, "cpu %lld %lld %lld %lld %lld %lld %lld %lld",
					&cpu_t_next.user, &cpu_t_next.nice, &cpu_t_next.system, &cpu_t_next.idle,
					&cpu_t_next.iowait, &cpu_t_next.irq, &cpu_t_next.softirq, &cpu_t_next.z);
	if (num >= 4) {
		idle_next = cpu_t_next.idle;
		total_next = cpu_t_next.user + cpu_t_next.nice + cpu_t_next.system + cpu_t_next.idle 
		+ cpu_t_next.iowait + cpu_t_next.irq + cpu_t_next.softirq + cpu_t_next.z;
	}
	fclose(fp);
	
	/* calculate cpu_usage_rate which is a global varible*/
	if (total_next != total_pre) {
		cpu_usage_rate = 1-((float)idle_next - (float)idle_pre)/((float)total_next - (float)total_pre);
		fprintf(stderr, "The CPU usage rate: %.0f%%\n", cpu_usage_rate*100);

		return 0;
	}
	else
		return -1;
}

/*
 *		Function:	int mem_stat(void)
 *		
 *		Purpose:	Statitic the memory usage rate
 *
 *		Argument:   None
 *		
 *		Return:		Success:0	Failure:-1
 */
int mem_stat(void)
{
	FILE *fp = NULL;
	unsigned int num = 0;
	unsigned int read_byte = 0;
	unsigned long long mem_total = 0;
	unsigned long long mem_free = 0;
	char *position = NULL;
	char buf[BUFSIZE - 1] = {0}; 
	
	fp = fopen("/proc/meminfo", "rb");
	if (!fp) {
		fprintf(stderr, "Unable to open /proc/stat");
		return -1;
	}
	
	read_byte = fread(buf, 1, sizeof(buf), fp);
	fclose(fp);
	if (read_byte == 0)
		return -1;
	
	if (buf != NULL && strlen(buf) > 0)
		position = strstr(buf, "MemTotal:");

	if (position == NULL)
		return -1;
	
	num = sscanf(position, "MemTotal:	 %lld", &mem_total);
	if (num != 1)
		return -1;

	if (position != NULL && strlen(position) > 0)
		position = strstr(position, "MemFree:");

	if (position == NULL)
		return -1;
	
	num = sscanf(position, "MemFree:	 %lld", &mem_free);
	if (num != 1)
		return -1;
	
	/* calculate mem_usage_rate which is a global varible*/
	if (mem_total) {
		mem_usage_rate = ((float)mem_total - (float)mem_free)/(float)mem_total;
		fprintf(stderr, "The memory usage rate: %.0f%%\n", mem_usage_rate*100);

		return 0;
	}
	else
		return -1;

}

/*
 *		Function:	int fs_stat(void)
 *		
 *		Purpose:	Statitic the log filesystem usage rate
 *
 *		Argument:   None
 *		
 *		Return:		Success:0	Failure:-1
 */
int fs_stat(void)	
{ 
	struct statvfs stat;
	char *path = "/var/log"; 
	
	memset(&stat, 0, sizeof(struct statvfs));
	/* get the information about the partition which the path is in */
	if(statvfs(path, &stat) == -1)
		return -1;
	
	/* calculate fs_usage_rate which is a global varible*/
	if (stat.f_blocks) {
		fs_usage_rate = ((float)stat.f_blocks-(float)stat.f_bfree)/(float)stat.f_blocks;
		fprintf(stderr, "The log filesystem: Total=%ldK Free=%ldK Usage rate=%.0f%%\n", 
			stat.f_bsize*stat.f_blocks/1024, stat.f_bsize*stat.f_bfree/1024, 100*fs_usage_rate);
	}
	
	return 0;
}