如何获得更高的"CPU％"精度?比从TOP命令得到的还要多? [英] How to get higher precision of "CPU%" than that from TOP command?

问题描述

当我使用TOP命令时，可以获得以下信息:

When I use TOP command, I could get the following info:

shell@android:/ $ top -n 1                                                     

User 31%, System 10%, IOW 0%, IRQ 0%
User 346 + Nice 10 + Sys 120 + Idle 637 + IOW 6 + IRQ 0 + SIRQ 2 = 1121

  PID PR CPU% S  #THR     VSS     RSS PCY UID      Name
  481  1  26% S    89 762832K  81688K  fg system   system_server
 1699  0   5% S    27 676472K  39092K  fg u0_a72   wm.cs.systemmonitor
11243  0   3% S    28 673140K  29796K  bg u0_a111  com.weather.Weather
13327  2   1% S    23 680472K  35844K  bg u0_a83   com.rhmsoft.fm
  659  0   1% S    17 663044K  33136K  bg u0_a13   android.process.media
20260  1   0% R     1   1208K    508K     shell    top

我们可以看到CPU%是四舍五入到整数，有什么办法可以使进程的CPU%精度更高?

We can see the CPU% is round to integer, is there any way I could get a process's CPU% with higher precision?

-关于赏金的说明- Alex

-- Clarifications on the bounty -- Alex

该问题针对的是Android系统，最好是针对非root用户的设备.尽管Android为Java应用程序提供了高级分析技术，但用于本机代码(C ++)的工具却受到限制. Android上的 top 命令允许显示系统中运行的所有线程(Java线程和C ++线程)的统计信息.我正在寻找对以下任务有帮助的答案:

The question refers to Android system, and preferably to a non-rooted device. While Android provides advanced profiling techniques for Java applications, tools for native code (C++) are limited. top command on Android allows to show the statistics for all threads running in the system, both Java threads and C++ threads. I am looking for an answer that will help with the following quest:

我的应用在后台处于非活动状态时使用2％的CPU，但应低于0.1％.如果我运行 top -t ，则属于我的进程的所有15个线程都将获得0％(某些线程是Java线程，例如Main，UI线程；其他线程是从不附加到JVM的p线程) .我怎么猜哪个线程会吃掉电池?

我很乐意获得有关此意外活动的更多详细信息，Android提供了诸如 TraceView (用于Java线程).对于本机代码工具的任何见解将受到高度赞赏.

I would be glad to get even more details about this unexpected activity, and Android provides great helpers like TraceView for Java threads. Any insight regarding tools for native code will be highly appreciated.

推荐答案

您在文章中没有提到它，但是在注释中您说您确实需要每个线程而不是每个进程的CPU利用率.

You didn't mention it in your post, but in the comment you said that you really need CPU utilization per thread, not per process.

如果找不到足够准确的工具，则可以按照

If you can't find a tool that's accurate enough, you can look directly in /proc/[pid]/task/[ThreadName] as described in the man page for /proc. This gives total CPU time consumed in "clock ticks" since execution began. Getting better resolution than this is probably difficult or impossible.

修改

在OP的注释中，列出相关信息的命令是:

From the OP's comment, a command that lists the relevant information is:

adb shell cat /proc/${pid}/task/*/stat | awk -F\ '{print $1, $14}' 

这只是将正确的/proc文件提供给调试主机，调试主机运行一个很小的awk程序以打印pid和user time的列.如果awk不可用，您还可以轻松地使用cut -d " " -f1,14或perl中的类似内容来获取列.

This just cats the correct /proc files to the debugging host, which runs a tiny awk program to print the columns for pid and user time. You could also easily use cut -d " " -f1,14 or something similar in perl to get the columns if awk isn't available.

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