最简单的工具来测量Linux中C程序缓存的命中率/未命中率和cpu时间? [英] simplest tool to measure C program cache hit/miss and cpu time in linux?

问题描述

我正在用C编写一个小程序，我想衡量它的性能.

I'm writing a small program in C, and I want to measure it's performance.

我想看看它在处理器中运行了多少时间，以及它造成了多少次高速缓存命中+未命中.关于上下文切换和内存使用的信息也将很高兴.

I want to see how much time do it run in the processor and how many cache hit+misses has it made. Information about context switches and memory usage would be nice to have too.

程序执行不到一秒钟.

我喜欢/proc/[pid]/stat的信息，但是我不知道程序死/被杀死后如何查看.

I like the information of /proc/[pid]/stat, but I don't know how to see it after the program has died/been killed.

有什么想法吗?

编辑:我认为Valgrind会增加很多开销.这就是为什么我想要一个始终可用的简单工具，例如/proc/[pid]/stat.

I think Valgrind adds a lot of overhead. That's why I wanted a simple tool, like /proc/[pid]/stat, that is always there.

推荐答案

使用性能:

perf stat ./yourapp

有关详细信息，请参见内核Wiki性能教程.这使用了CPU的硬件性能计数器，因此开销非常小.

See the kernel wiki perf tutorial for details. This uses the hardware performance counters of your CPU, so the overhead is very small.

来自Wiki的示例:

perf stat -B dd if=/dev/zero of=/dev/null count=1000000

Performance counter stats for 'dd if=/dev/zero of=/dev/null count=1000000':

        5,099 cache-misses             #      0.005 M/sec (scaled from 66.58%)
      235,384 cache-references         #      0.246 M/sec (scaled from 66.56%)
    9,281,660 branch-misses            #      3.858 %     (scaled from 33.50%)
  240,609,766 branches                 #    251.559 M/sec (scaled from 33.66%)
1,403,561,257 instructions             #      0.679 IPC   (scaled from 50.23%)
2,066,201,729 cycles                   #   2160.227 M/sec (scaled from 66.67%)
          217 page-faults              #      0.000 M/sec
            3 CPU-migrations           #      0.000 M/sec
           83 context-switches         #      0.000 M/sec
   956.474238 task-clock-msecs         #      0.999 CPUs

   0.957617512  seconds time elapsed

无需手动加载内核模块，在现代的debian系统(带有linux-base软件包)上，它应该可以正常工作.使用perf record -a/perf report组合，您还可以进行完整的系统分析.任何带有调试符号的应用程序或库都将在报告中显示详细信息.

No need to load a kernel module manually, on a modern debian system (with the linux-base package) it should just work. With the perf record -a / perf report combo you can also do full-system profiling. Any application or library that has debugging symbols will show up with details in the report.

为了可视化，火焰图看起来效果很好. (2020年更新:热点用户界面集成了火焰图.)

For visualization flame graphs seem to work well. (Update 2020: the hotspot UI has flame graphs integrated.)

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