位置: IT常识 - 正文

Linux中计算特定CPU使用率案例详解(linux 计算字符数)

编辑:rootadmin
这篇文章主要介绍了Linux中计算特定CPU使用率案例详解,本篇文章通过简要的案例,讲解了该项技术的了解与使用,以下就是详细内容,需要的朋友可以参考下... 21-09-02

推荐整理分享Linux中计算特定CPU使用率案例详解(linux 计算字符数),希望有所帮助,仅作参考,欢迎阅读内容。

文章相关热门搜索词:linux怎么计算,linux计算pi,linux运算,linux运算,linux 计算命令,linux 算数,linux计算pi,linux计算sha1,内容如对您有帮助,希望把文章链接给更多的朋友!

Linux中计算特定CPU使用率 需求解决方案拓展参考

需求

在Linux中可以通过top指令查看某一进程占用的CPU情况,也可以查看某一个CPU使用率情况(先top指令,然后按数字“1”键即可显示每一个CPU的使用情况),如下图:

而我们的需求是:如何得到一个CPU的占用率呢?

解决方案

1. 背景知识

在/proc/stat中可以查看每一个CPU的使用情况的,如下图:

Linux中计算特定CPU使用率案例详解(linux 计算字符数)

其中cpu(0/1/2/…)后面的那十个数字含义如下:

/proc/statkernel/system statistics. Varies with architecture. Common entries include:user nice system idle iowait irq softirq steal guest guest_nicecpu 4705 356 584 3699 23 23 0 0 0 0cpu0 1393280 32966 572056 13343292 6130 0 17875 0 23933 0The amount of time, measured in units of USER_HZ(1/100ths of a second on most architectures, usesysconf(_SC_CLK_TCK) to obtain the right value), thatthe system ("cpu" line) or the specific CPU ("cpuN"line) spent in various states:user (1) Time spent in user mode.nice (2) Time spent in user mode with low priority(nice).system (3) Time spent in system mode.idle (4) Time spent in the idle task. This valueshould be USER_HZ times the second entry in the/proc/uptime pseudo-file.iowait (since Linux 2.5.41)(5) Time waiting for I/O to complete. Thisvalue is not reliable, for the following rea‐sons:1. The CPU will not wait for I/O to complete;iowait is the time that a task is waiting forI/O to complete. When a CPU goes into idlestate for outstanding task I/O, another taskwill be scheduled on this CPU.2. On a multi-core CPU, the task waiting for I/Oto complete is not running on any CPU, so theiowait of each CPU is difficult to calculate.3. The value in this field may decrease in cer‐tain conditions.irq (since Linux 2.6.0-test4)(6) Time servicing interrupts.softirq (since Linux 2.6.0-test4)(7) Time servicing softirqs.steal (since Linux 2.6.11)(8) Stolen time, which is the time spent inother operating systems when running in a virtu‐alized environmentguest (since Linux 2.6.24)(9) Time spent running a virtual CPU for guestoperating systems under the control of the Linuxkernel.guest_nice (since Linux 2.6.33)(10) Time spent running a niced guest (virtualCPU for guest operating systems under the con‐trol of the Linux kernel).

2.计算具体CPU使用率

有了上面的背景知识,接下来我们就可以计算具体CPU的使用情况了。具体计算方式如下:

Total CPU time since boot = user+nice+system+idle+iowait+irq+softirq+stealTotal CPU Idle time since boot = idle + iowaitTotal CPU usage time since boot = Total CPU time since boot-Total CPU Idle time since bootTotal CPU percentage = Total CPU usage time since boot/Total CPU time since boot * 100%

有了上面的计算公式,计算某一CPU使用率或者系统总的CPU占用率也就是不难了。示例:计算系统整体CPU占用情况首先从/proc/stat中获取 t1时刻系统总体的user、nice、system、idle、iowait、irq、softirq、steal、guest、guest_nice的值,得到此时Total CPU time since boot(记为total1)和 Total CPU idle time since boot(记为idle1)。其次,从/proc/stat中获取t2时刻系统总的Total CPU time since boot(记为total2)和Total CPU idle time since boot(记为idle2)。(方法同上一步)最后,计算t2与t1之间系统总的CPU使用情况。也就是:CPU percentage between t1 and t2 = ((total2-total1)-(idle2-idle1))/(total2-total1)* 100%其中, ((total2-total1)-(idle2-idle1))实际上就是t1与t2时刻之间系统CPU被占用的时间(总时间-空闲时间)。下面是一段计算时间段内CPU被占用情况的脚本:

#!/bin/bash# by Paul Colby (http://colby.id.au), no rights reserved ;)PREV_TOTAL=0PREV_IDLE=0while true; do# Get the total CPU statistics, discarding the 'cpu ' prefix.CPU=(`sed -n 's/^cpu\s//p' /proc/stat`)IDLE=${CPU[3]} # Just the idle CPU time.# Calculate the total CPU time.TOTAL=0for VALUE in "${CPU[@]}"; dolet "TOTAL=$TOTAL+$VALUE"done# Calculate the CPU usage since we last checked.let "DIFF_IDLE=$IDLE-$PREV_IDLE"let "DIFF_TOTAL=$TOTAL-$PREV_TOTAL"let "DIFF_USAGE=(1000*($DIFF_TOTAL-$DIFF_IDLE)/$DIFF_TOTAL+5)/10"echo -en "\rCPU: $DIFF_USAGE% \b\b"# Remember the total and idle CPU times for the next check.PREV_TOTAL="$TOTAL"PREV_IDLE="$IDLE"# Wait before checking again.sleep 1done拓展

在内核中,关于/proc/stat中文件的实现函数如下:

附注:内核版本3.14.69,文件为 /fs/proc/stat.c#include <linux/cpumask.h>#include <linux/fs.h>#include <linux/init.h>#include <linux/interrupt.h>#include <linux/kernel_stat.h>#include <linux/proc_fs.h>#include <linux/sched.h>#include <linux/seq_file.h>#include <linux/slab.h>#include <linux/time.h>#include <linux/irqnr.h>#include <asm/cputime.h>#include <linux/tick.h>#ifndef arch_irq_stat_cpu#define arch_irq_stat_cpu(cpu) 0#endif#ifndef arch_irq_stat#define arch_irq_stat() 0#endif#ifdef arch_idle_timestatic cputime64_t get_idle_time(int cpu){cputime64_t idle;idle = kcpustat_cpu(cpu).cpustat[CPUTIME_IDLE];if (cpu_online(cpu) && !nr_iowait_cpu(cpu))idle += arch_idle_time(cpu);return idle;}static cputime64_t get_iowait_time(int cpu){cputime64_t iowait;iowait = kcpustat_cpu(cpu).cpustat[CPUTIME_IOWAIT];if (cpu_online(cpu) && nr_iowait_cpu(cpu))iowait += arch_idle_time(cpu);return iowait;}#elsestatic u64 get_idle_time(int cpu){u64 idle, idle_time = -1ULL;if (cpu_online(cpu))idle_time = get_cpu_idle_time_us(cpu, NULL);if (idle_time == -1ULL)/* !NO_HZ or cpu offline so we can rely on cpustat.idle */idle = kcpustat_cpu(cpu).cpustat[CPUTIME_IDLE];elseidle = usecs_to_cputime64(idle_time);return idle;}static u64 get_iowait_time(int cpu){u64 iowait, iowait_time = -1ULL;if (cpu_online(cpu))iowait_time = get_cpu_iowait_time_us(cpu, NULL);if (iowait_time == -1ULL)/* !NO_HZ or cpu offline so we can rely on cpustat.iowait */iowait = kcpustat_cpu(cpu).cpustat[CPUTIME_IOWAIT];elseiowait = usecs_to_cputime64(iowait_time);return iowait;}#endifstatic int show_stat(struct seq_file *p, void *v){int i, j;unsigned long jif;u64 user, nice, system, idle, iowait, irq, softirq, steal;u64 guest, guest_nice;u64 sum = 0;u64 sum_softirq = 0;unsigned int per_softirq_sums[NR_SOFTIRQS] = {0};struct timespec boottime;user = nice = system = idle = iowait =irq = softirq = steal = 0;guest = guest_nice = 0;getboottime(&boottime);jif = boottime.tv_sec;for_each_possible_cpu(i) {user += kcpustat_cpu(i).cpustat[CPUTIME_USER];nice += kcpustat_cpu(i).cpustat[CPUTIME_NICE];system += kcpustat_cpu(i).cpustat[CPUTIME_SYSTEM];idle += get_idle_time(i);iowait += get_iowait_time(i);irq += kcpustat_cpu(i).cpustat[CPUTIME_IRQ];softirq += kcpustat_cpu(i).cpustat[CPUTIME_SOFTIRQ];steal += kcpustat_cpu(i).cpustat[CPUTIME_STEAL];guest += kcpustat_cpu(i).cpustat[CPUTIME_GUEST];guest_nice += kcpustat_cpu(i).cpustat[CPUTIME_GUEST_NICE];sum += kstat_cpu_irqs_sum(i);sum += arch_irq_stat_cpu(i);for (j = 0; j < NR_SOFTIRQS; j++) {unsigned int softirq_stat = kstat_softirqs_cpu(j, i);per_softirq_sums[j] += softirq_stat;sum_softirq += softirq_stat;}}sum += arch_irq_stat();seq_puts(p, "cpu ");seq_put_decimal_ull(p, ' ', cputime64_to_clock_t(user));seq_put_decimal_ull(p, ' ', cputime64_to_clock_t(nice));seq_put_decimal_ull(p, ' ', cputime64_to_clock_t(system));seq_put_decimal_ull(p, ' ', cputime64_to_clock_t(idle));seq_put_decimal_ull(p, ' ', cputime64_to_clock_t(iowait));seq_put_decimal_ull(p, ' ', cputime64_to_clock_t(irq));seq_put_decimal_ull(p, ' ', cputime64_to_clock_t(softirq));seq_put_decimal_ull(p, ' ', cputime64_to_clock_t(steal));seq_put_decimal_ull(p, ' ', cputime64_to_clock_t(guest));seq_put_decimal_ull(p, ' ', cputime64_to_clock_t(guest_nice));seq_putc(p, '\n');for_each_online_cpu(i) {/* Copy values here to work around gcc-2.95.3, gcc-2.96 */user = kcpustat_cpu(i).cpustat[CPUTIME_USER];nice = kcpustat_cpu(i).cpustat[CPUTIME_NICE];system = kcpustat_cpu(i).cpustat[CPUTIME_SYSTEM];idle = get_idle_time(i);iowait = get_iowait_time(i);irq = kcpustat_cpu(i).cpustat[CPUTIME_IRQ];softirq = kcpustat_cpu(i).cpustat[CPUTIME_SOFTIRQ];steal = kcpustat_cpu(i).cpustat[CPUTIME_STEAL];guest = kcpustat_cpu(i).cpustat[CPUTIME_GUEST];guest_nice = kcpustat_cpu(i).cpustat[CPUTIME_GUEST_NICE];seq_printf(p, "cpu%d", i);seq_put_decimal_ull(p, ' ', cputime64_to_clock_t(user));seq_put_decimal_ull(p, ' ', cputime64_to_clock_t(nice));seq_put_decimal_ull(p, ' ', cputime64_to_clock_t(system));seq_put_decimal_ull(p, ' ', cputime64_to_clock_t(idle));seq_put_decimal_ull(p, ' ', cputime64_to_clock_t(iowait));seq_put_decimal_ull(p, ' ', cputime64_to_clock_t(irq));seq_put_decimal_ull(p, ' ', cputime64_to_clock_t(softirq));seq_put_decimal_ull(p, ' ', cputime64_to_clock_t(steal));seq_put_decimal_ull(p, ' ', cputime64_to_clock_t(guest));seq_put_decimal_ull(p, ' ', cputime64_to_clock_t(guest_nice));seq_putc(p, '\n');}seq_printf(p, "intr %llu", (unsigned long long)sum);/* sum again ? it could be updated? */for_each_irq_nr(j)seq_put_decimal_ull(p, ' ', kstat_irqs_usr(j));seq_printf(p,"\nctxt %llu\n""btime %lu\n""processes %lu\n""procs_running %lu\n""procs_blocked %lu\n",nr_context_switches(),(unsigned long)jif,total_forks,nr_running(),nr_iowait());seq_printf(p, "softirq %llu", (unsigned long long)sum_softirq);for (i = 0; i < NR_SOFTIRQS; i++)seq_put_decimal_ull(p, ' ', per_softirq_sums[i]);seq_putc(p, '\n');return 0;}static int stat_open(struct inode *inode, struct file *file){size_t size = 1024 + 128 * num_possible_cpus();char *buf;struct seq_file *m;int res;/* minimum size to display an interrupt count : 2 bytes */size += 2 * nr_irqs;/* don't ask for more than the kmalloc() max size */if (size > KMALLOC_MAX_SIZE)size = KMALLOC_MAX_SIZE;buf = kmalloc(size, GFP_KERNEL);if (!buf)return -ENOMEM;res = single_open(file, show_stat, NULL);if (!res) {m = file->private_data;m->buf = buf;m->size = ksize(buf);} elsekfree(buf);return res;}static const struct file_operations proc_stat_operations = {.open= stat_open,.read= seq_read,.llseek= seq_lseek,.release= single_release,};static int __init proc_stat_init(void){proc_create("stat", 0, NULL, &proc_stat_operations);return 0;}fs_initcall(proc_stat_init);参考

http://man7.org/linux/man-pages/man5/proc.5.html

https://github.com/pcolby/scripts/blob/master/cpu.sh

https://elixir.bootlin.com/linux/v3.14.69/source/fs/proc/stat.c

到此这篇关于Linux中计算特定CPU使用率案例详解的文章就介绍到这了,更多相关Linux中计算特定CPU使用率内容请搜索电脑学习网以前的文章或继续浏览下面的相关文章,希望大家以后多多支持电脑学习网!

本文链接地址:https://www.jiuchutong.com/zhishi/278044.html 转载请保留说明!

上一篇:爱荷华州中部的高架栈桥 (© Kelly van Dellen/Getty Images Plus)(爱荷华州的首府)

下一篇:mhotkey.exe是什么进程 有什么作用 mhotkey进程查询(onekey.exe是什么)

  • 摊薄净资产收益率是什么意思
  • 银行贴现属于贷款吗
  • 现金折扣的销售额
  • 营改增企业所得税
  • 装饰设计事务所平面图
  • 制造费用计入营业成本吗
  • 融资租赁开具的发票是货物还是租金
  • 怎么从银行买承兑汇票
  • 支票存根联要带去银行吗
  • 小规模收到货运专用发票
  • 报企业所得税的利润总额怎么填
  • 小微企业减免税如何算
  • 去国税申请开票需要法人和财务去吗?
  • 证券投资基金管理办法
  • 小规模纳税人金额
  • 增值税记账流程
  • 六税两费减半征收政策2022
  • 如何计算工程预付款
  • 以旧机器抵货款合法吗
  • 外经证金额没开完需要核销吗
  • 小规模公司税控盘维护费会计分录
  • 公司的资产负债表包括
  • 购入商品款项尚未入库
  • vivo手机可以安装鸿蒙
  • 期间费用率的意义
  • 长期待摊费用科目还用吗
  • win7系统中回收站的内容清空后还能恢复吗
  • 琼斯的大海怪
  • 工业企业会计核算的特点
  • ati2sgag.exe进程安全吗 ati2sgag进程信息查询
  • 银行公户转账需要带什么
  • ipad3性价比
  • 几款常用的表单设计软件
  • 制作个性化的奖杯或者奖状
  • php购物车实现流程
  • wx-java
  • php怎么调用图片
  • ps如何打圈内环形文字怎么调间距
  • 管理费用怎么入账
  • 现代服务增值税纳税义务发生时间
  • 银行回单箱费会退回吗
  • 开源 okr
  • 土方工程开票
  • 核销坏账递延资产怎么算
  • 外币交易的会计分录怎么写
  • win10下安装win7启动不了
  • mysql语句性能优化
  • 付给对方钱对方应该怎么写
  • 原材料的对应账户有哪些
  • 以前年度漏扣个税怎么处理
  • 旅行社增值税2020
  • 营业税暂行实施细则
  • 销售退货的会计账怎么处理
  • 当月的银行日记账漏计怎么办
  • 装修费应该按几折算
  • 已经确认收入
  • 注册资金未缴齐怎么处理
  • 培训费产生的差额是什么
  • 在建工程不做了发生的费用如何做账?
  • 如何使用u盘安装win11
  • win8系统的运行在哪里打开
  • win10 64位开机卡在登录界面的解决办法
  • 服务器centos版本选择
  • Ubuntu系统怎么设置root
  • linux用户账户管理
  • win10地图不显示
  • linux中tail命令详解
  • win10更新后有线网络无法使用
  • 如何在linux shell关闭443端口
  • linux服务器安全配置
  • Unity3d_NGUI和UGUI的学习
  • ExtJS4利根据登录后不同的角色分配不同的树形菜单
  • 不易引起无意注意的是
  • Nodejs事件循环机制图解
  • javascript怎么学
  • javascript中函数的作用域分为全局作用域
  • 如何加强税务系统财务管理工作
  • 北京西城税务局
  • 组织创新包括哪些类型
  • 资源税原矿和选矿的区别
  • 免责声明:网站部分图片文字素材来源于网络,如有侵权,请及时告知,我们会第一时间删除,谢谢! 邮箱:opceo@qq.com

    鄂ICP备2023003026号

    网站地图: 企业信息 工商信息 财税知识 网络常识 编程技术

    友情链接: 武汉网站建设