C 在 linux 和 windows 上获取 CPU 使用率
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C get cpu usage on linux and windows
提问by Enjoy coding
I am using below programs on linux and windows to get cpu utilization of current processes.
我在 linux 和 windows 上使用以下程序来获取当前进程的 CPU 利用率。
Linux:
Linux：
int main()
{
int ret;
char *buf;
int i=0;
int who= RUSAGE_SELF;
struct rusage usage;
struct rusage *p=&usage;
ret=getrusage(who,p);
printf("user time used: %16lf %16lf\n",p->ru_utime.tv_sec,p->ru_utime.tv_usec);
printf("system time used: %16lf %16lf\n",p->ru_stime.tv_sec,p->ru_stime.tv_usec);
system("ls");
printf("user time used: %16lf %16lf\n",p->ru_utime.tv_sec,p->ru_utime.tv_usec);
printf("system time used: %16lf %16lf\n", p->ru_stime.tv_sec,p->ru_stime.tv_usec);
return 0;
}
Output on linux:
linux上的输出：
user time used: 0.000000 -1.999568
system time used: 0.000000 -1.999568
a.out check.c
user time used: 0.000000 -1.999568
system time used: 0.000000 -1.999568
Does this mean that the system("ls") command did not take any cpu cycles to execute? How do i get the exact cpu cycles used by any command or program?
这是否意味着 system("ls") 命令没有执行任何 CPU 周期？我如何获得任何命令或程序使用的确切 CPU 周期？
I am facing similar problems on windows. for the below code.
我在 Windows 上面临类似的问题。对于下面的代码。
Windows:
视窗：
int main()
{
int i=0;
HANDLE hProcess = GetCurrentProcess();
FILETIME ftCreation, ftExit, ftKernel, ftUser;
SYSTEMTIME stKernel;
SYSTEMTIME stUser;
GetProcessTimes(hProcess, &ftCreation, &ftExit, &ftKernel, &ftUser);
FileTimeToSystemTime(&ftKernel, &stKernel);
FileTimeToSystemTime(&ftUser, &stUser);
printf("\nTime in kernel mode = %uh %um %us %ums", stKernel.wHour,stKernel.wMinute, stKernel.wSecond, stKernel.wMilliseconds);
printf("\nTime in user mode = %uh %um %us %ums \n", stUser.wHour,stUser.wMinute, stUser.wSecond, stUser.wMilliseconds);
system("dir");
GetProcessTimes(hProcess, &ftCreation, &ftExit, &ftKernel, &ftUser);
FileTimeToSystemTime(&ftKernel, &stKernel);
FileTimeToSystemTime(&ftUser, &stUser);
printf("\nTime in kernel mode = %uh %um %us %ums", stKernel.wHour,stKernel.wMinute, stKernel.wSecond, stKernel.wMilliseconds);
printf("\nTime in user mode = %uh %um %us %ums \n", stUser.wHour,stUser.wMinute, stUser.wSecond, stUser.wMilliseconds);
system("PAUSE");
return 0;
}
Above program output on windowsdev c++:
以上程序输出在 windowsdev c++ 上：
Time in kernel mode: 0h 0m 0s 15ms
Time in user mode: 0h 0m 0s 15ms
<directory listing>
Time in kernel mode: 0h 0m 0s 15ms
Time in user mode: 0h 0m 0s 15ms
Can you please let me know how can we get correct cpu usage for the above programs? Also is there a way to get to know IO usage or number of characters read and write to disk/memory? Thanks in advance.
您能否让我知道我们如何为上述程序获得正确的 CPU 使用率？还有一种方法可以了解 IO 使用情况或读写磁盘/内存的字符数吗？提前致谢。
回答by Adrian Cox
In the Linux version you've asked for RUSAGE_SELF, which is all threads of the parent process, rather than RUSAGE_CHILDRENfor child processes. For IO usage under Linux you'll need a kernel after 2.6.20, and look in /proc/[pid]/io.
在您要求的 Linux 版本中RUSAGE_SELF，它是父进程的所有线程，而不是RUSAGE_CHILDREN子进程。对于 Linux 下的 IO 使用，您需要 2.6.20 之后的内核，并查看/proc/[pid]/io.
I think you have a similar problem on Windows. You'll need to use CreateProcessrather than system, so that you can get a handle to the child process and record its times. For IO usage on windows I think you'll need to use WMI, which is a large subject.
我认为您在 Windows 上也有类似的问题。您需要使用CreateProcess而不是system，以便您可以获得子进程的句柄并记录其时间。对于 Windows 上的 IO 使用，我认为您需要使用 WMI，这是一个很大的主题。
回答by Thunder Liu
You made a few errors in the linux version here.
您在此处的 linux 版本中犯了一些错误。
- As Adrian pointed out, you should use
RUSAGE_CHILDRENto count in the resource consumed by the child process. - You did not call
getrusage()again after you invokedsystem(). In your
printf(), you should not use%lfwhich represents a long double type.tv_secis of typetime_tandtv_usecis of typesusecond_t. In 64-bit linux, they are bothsigned long, which is incompatible withlong double(note you have negative result here). For portability, you should have used explicit cast, such as:printf("user time used: %ld %ld\n",(long)p->ru_utime.tv_sec,(long)p->ru_utime.tv_usec);
- 正如 Adrian 所指出的，您应该使用
RUSAGE_CHILDREN来计算子进程消耗的资源。 - 调用
getrusage()后没有再次调用system()。 在您的 中
printf()，您不应使用%lfwhich 代表 long double 类型。tv_sec属于 类型time_t并且tv_usec属于 类型susecond_t。在 64 位 linux 中，它们都是signed long，这是不兼容的long double（注意这里有否定结果）。为了可移植性，您应该使用显式转换，例如：printf("user time used: %ld %ld\n",(long)p->ru_utime.tv_sec,(long)p->ru_utime.tv_usec);
回答by Lightness Races in Orbit
It is the correct output. lsis not the current process; whilst lsis executing, no CPU time is spent on your process.
这是正确的输出。ls不是当前进程；在ls执行过程中，您的进程不会花费任何 CPU 时间。
BTW Dev-C++ is just a [bad, unmaintained] IDE, not a compiler. You probably meant to say MinGW.
顺便说一句，Dev-C++ 只是一个 [糟糕的、未维护的] IDE，而不是编译器。您可能想说的是 MinGW。
