Linux 应用程序分析

Question

如何在 Linux 机器上记录应用程序的性能？我不会有 IDE。

理想情况下，我需要一个将附加到进程并记录定期快照的应用程序:

• 内存使用情况
• 线程数
• CPU 使用率

Answer 1

Ideally, I need an application that will attach to a process and log periodic snapshots of:

• memory usage
• number of threads
• CPU usage

好吧，为了收集有关您的进程的此类信息，您实际上并不需要 Linux 上的分析器。

1. 您可以在批处理模式下使用 top。它以批处理模式运行，直到它被杀死或完成 N 次迭代:

   top -b -p `pidof a.out`
   

   或
   

   top -b -p `pidof a.out` -n 100
   

   你会得到这个:

   $ top -b -p `pidof a.out`
   
   top - 10:31:50 up 12 days, 19:08,  5 users,  load average: 0.02, 0.01, 0.02
   Tasks:   1 total,   0 running,   1 sleeping,   0 stopped,   0 zombie
   Cpu(s):  0.0%us,  0.0%sy,  0.0%ni,100.0%id,  0.0%wa,  0.0%hi,  0.0%si,  0.0%st
   Mem:  16330584k total,  2335024k used, 13995560k free,   241348k buffers
   Swap:  4194296k total,        0k used,  4194296k free,  1631880k cached
   
     PID USER      PR  NI  VIRT  RES  SHR S %CPU %MEM    TIME+  COMMAND
   24402 SK        20   0 98.7m 1056  860 S 43.9  0.0   0:11.87 a.out
   
   
   top - 10:31:53 up 12 days, 19:08,  5 users,  load average: 0.02, 0.01, 0.02
   Tasks:   1 total,   0 running,   1 sleeping,   0 stopped,   0 zombie
   Cpu(s):  0.9%us,  3.7%sy,  0.0%ni, 95.5%id,  0.0%wa,  0.0%hi,  0.0%si,  0.0%st
   Mem:  16330584k total,  2335148k used, 13995436k free,   241348k buffers
   Swap:  4194296k total,        0k used,  4194296k free,  1631880k cached
   
   PID USER      PR  NI  VIRT  RES  SHR S %CPU %MEM    TIME+  COMMAND
   24402 SK      20   0 98.7m 1072  860 S 19.0  0.0   0:12.44 a.out
   

2. 您可以使用 ps(例如在 shell 脚本中)
   

   ps --format pid,pcpu,cputime,etime,size,vsz,cmd -p `pidof a.out`
   

   ---

   I need some means of recording the performance of an application on a Linux machine

   如果您的 Linux 内核大于 2.6.32 或 OProfile，您需要使用 perf 来执行此操作如果它更旧。这两个程序都不需要您来检测您的程序(如 Gprof 需要)。但是，为了在 perf 中正确获取调用图，您需要使用 -fno-omit-frame-pointer 构建程序。例如:g++ -fno-omit-frame-pointer -O2 main.cpp.

至于Linux perf:

1. 记录性能数据:

   perf record -p `pidof a.out`
   

   或录制 10 秒:

   perf record -p `pidof a.out` sleep 10
   

   或者用调用图记录()

   perf record -g -p `pidof a.out`
   

2. 分析记录的数据

   perf report --stdio
   perf report --stdio --sort=dso -g none
   perf report --stdio -g none
   perf report --stdio -g
   

   开启 RHEL 6.3 允许读取/boot/System.map-2.6.32-279.el6.x86_64，所以我一般在做的时候加上--kallsyms=/boot/System.map-2.6.32-279.el6.x86_64业绩报告:

   perf report --stdio -g --kallsyms=/boot/System.map-2.6.32-279.el6.x86_64
   

   ---

   这里我写了一些关于使用 Linux `perf` 的更多信息:

   首先 - 这是tutorial about Linux profiling with perf

   如果您的 Linux 内核大于 2.6.32，您可以使用 perf，如果它较旧，您可以使用 OProfile。这两个程序都不需要你来检测你的程序(就像 Gprof 需要的那样)。但是，为了在 perf 中正确获取调用图，您需要使用 -fno-omit-frame-pointer 构建程序。例如:g++ -fno-omit-frame-pointer -O2 main.cpp.

   您可以使用 perf top 查看对您的应用程序的“实时”分析:

    sudo perf top -p `pidof a.out` -K
   

 

或者您可以记录正在运行的应用程序的性能数据并在之后进行分析:

1. 记录性能数据:

   perf record -p `pidof a.out`
   

   或录制 10 秒:

   perf record -p `pidof a.out` sleep 10
   

   或者用调用图记录()

   perf record -g -p `pidof a.out`
   

2. 分析记录的数据

perf report --stdio
perf report --stdio --sort=dso -g none
perf report --stdio -g none
perf report --stdio -g

或者您可以记录应用程序的性能数据并在之后分析它们，只需以这种方式启动应用程序并等待它退出:

perf record ./a.out

这是一个分析测试程序的示例。

测试程序在文件main.cpp中(main.cpp在答案的底部):

我是这样编译的:

g++ -m64 -fno-omit-frame-pointer -g main.cpp -L.  -ltcmalloc_minimal -o my_test

我使用 libmalloc_minimial.so，因为它是用 -fno-omit-frame-pointer 编译的，而 libc malloc 似乎是在没有这个选项的情况下编译的。然后我运行我的测试程序:

./my_test 100000000

然后我记录一个正在运行的进程的性能数据:

perf record -g  -p `pidof my_test` -o ./my_test.perf.data sleep 30

然后我分析每个模块的负载:

perf report --stdio -g none --sort comm,dso -i ./my_test.perf.data

# Overhead  Command                 Shared Object
# ........  .......  ............................
#
    70.06%  my_test  my_test
    28.33%  my_test  libtcmalloc_minimal.so.0.1.0
     1.61%  my_test  [kernel.kallsyms]

然后分析每个函数的负载:

perf report --stdio -g none -i ./my_test.perf.data | c++filt

# Overhead  Command                 Shared Object                       Symbol
# ........  .......  ............................  ...........................
#
    29.30%  my_test  my_test                       [.] f2(long)
    29.14%  my_test  my_test                       [.] f1(long)
    15.17%  my_test  libtcmalloc_minimal.so.0.1.0  [.] operator new(unsigned long)
    13.16%  my_test  libtcmalloc_minimal.so.0.1.0  [.] operator delete(void*)
     9.44%  my_test  my_test                       [.] process_request(long)
     1.01%  my_test  my_test                       [.] operator delete(void*)@plt
     0.97%  my_test  my_test                       [.] operator new(unsigned long)@plt
     0.20%  my_test  my_test                       [.] main
     0.19%  my_test  [kernel.kallsyms]             [k] apic_timer_interrupt
     0.16%  my_test  [kernel.kallsyms]             [k] _spin_lock
     0.13%  my_test  [kernel.kallsyms]             [k] native_write_msr_safe

     and so on ...

然后分析调用链:

perf report --stdio -g graph -i ./my_test.perf.data | c++filt

# Overhead  Command                 Shared Object                       Symbol
# ........  .......  ............................  ...........................
#
    29.30%  my_test  my_test                       [.] f2(long)
            |
            --- f2(long)
               |
                --29.01%-- process_request(long)
                          main
                          __libc_start_main

    29.14%  my_test  my_test                       [.] f1(long)
            |
            --- f1(long)
               |
               |--15.05%-- process_request(long)
               |          main
               |          __libc_start_main
               |
                --13.79%-- f2(long)
                          process_request(long)
                          main
                          __libc_start_main

    15.17%  my_test  libtcmalloc_minimal.so.0.1.0  [.] operator new(unsigned long)
            |
            --- operator new(unsigned long)
               |
               |--11.44%-- f1(long)
               |          |
               |          |--5.75%-- process_request(long)
               |          |          main
               |          |          __libc_start_main
               |          |
               |           --5.69%-- f2(long)
               |                     process_request(long)
               |                     main
               |                     __libc_start_main
               |
                --3.01%-- process_request(long)
                          main
                          __libc_start_main

    13.16%  my_test  libtcmalloc_minimal.so.0.1.0  [.] operator delete(void*)
            |
            --- operator delete(void*)
               |
               |--9.13%-- f1(long)
               |          |
               |          |--4.63%-- f2(long)
               |          |          process_request(long)
               |          |          main
               |          |          __libc_start_main
               |          |
               |           --4.51%-- process_request(long)
               |                     main
               |                     __libc_start_main
               |
               |--3.05%-- process_request(long)
               |          main
               |          __libc_start_main
               |
                --0.80%-- f2(long)
                          process_request(long)
                          main
                          __libc_start_main

     9.44%  my_test  my_test                       [.] process_request(long)
            |
            --- process_request(long)
               |
                --9.39%-- main
                          __libc_start_main

     1.01%  my_test  my_test                       [.] operator delete(void*)@plt
            |
            --- operator delete(void*)@plt

     0.97%  my_test  my_test                       [.] operator new(unsigned long)@plt
            |
            --- operator new(unsigned long)@plt

     0.20%  my_test  my_test                       [.] main
     0.19%  my_test  [kernel.kallsyms]             [k] apic_timer_interrupt
     0.16%  my_test  [kernel.kallsyms]             [k] _spin_lock
     and so on ...

所以此时您知道您的程序将时间花在了哪里。

这是用于测试的 main.cpp 文件:

#include <stdio.h>
#include <stdlib.h>
#include <time.h>

time_t f1(time_t time_value)
{
  for (int j = 0; j < 10; ++j) {
    ++time_value;
    if (j%5 == 0) {
      double *p = new double;
      delete p;
    }
  }
  return time_value;
}

time_t f2(time_t time_value)
{
  for (int j = 0; j < 40; ++j) {
    ++time_value;
  }
  time_value = f1(time_value);
  return time_value;
}

time_t process_request(time_t time_value)
{
  for (int j = 0; j < 10; ++j) {
    int *p = new int;
    delete p;
    for (int m = 0; m < 10; ++m) {
      ++time_value;
    }
  }
  for (int i = 0; i < 10; ++i) {
    time_value = f1(time_value);
    time_value = f2(time_value);
  }
  return time_value;
}

int main(int argc, char* argv2[])
{
  int number_loops = argc > 1 ? atoi(argv2[1]) : 1;
  time_t time_value = time(0);
  printf("number loops %d\n", number_loops);
  printf("time_value: %d\n", time_value);

  for (int i = 0; i < number_loops; ++i) {
    time_value = process_request(time_value);
  }
  printf("time_value: %ld\n", time_value);
  return 0;
}