perf使调用图的demangling

如何为perf callgraph启用C ++ demangling? 当我进入注释模式时,似乎可以将符号去掉,但不会在主调用图中显示。

示例代码(使用Google Benchmark ):

#include <benchmark/benchmark.h> #include <vector> static __attribute__ ((noinline)) int my_really_big_function() { for(size_t i = 0; i < 1000; ++i) { benchmark::DoNotOptimize(i % 5); } return 0; } static __attribute__ ((noinline)) void caller1() { for(size_t i = 0; i < 1000; ++i) { benchmark::DoNotOptimize(my_really_big_function()); benchmark::DoNotOptimize(i % 5); } } static __attribute__ ((noinline)) void myfun(benchmark::State& state) { while(state.KeepRunning()) { caller1(); } } BENCHMARK(myfun); BENCHMARK_MAIN(); 

build立命令:

 clang++ main.cpp -o main -fno-omit-frame-pointer -O0 -lpthread -lbenchmark 

perf命令:

 perf record -g ./main perf report -g 'graph,0.5,caller' 

我也尝试启用–demangle选项,但似乎不影响输出。

callgraph缺lessdemangled符号:

 Samples: 3K of event 'cycles', Event count (approx.): 2946754102 Children Self Command Shared Object Symbol + 99.82% 0.00% main main [.] _ZL5myfunRN9benchmark5StateE + 99.82% 0.00% main main [.] _ZN9benchmark12_GLOBAL__N_111RunInThreadEPKNS_8internal9Benchmark8InstanceEmiPNS0_11ThreadStatsE + 99.82% 0.00% main main [.] _ZN9benchmark22RunSpecifiedBenchmarksEPNS_17BenchmarkReporterE + 99.82% 0.00% main main [.] main + 99.82% 0.00% main libc-2.21.so [.] __libc_start_main + 99.82% 0.00% main [unknown] [.] 0x7fbe258d4c544155 + 99.75% 0.30% main main [.] _ZL7caller1v + 99.52% 99.46% main main [.] _ZL22my_really_big_functionv 

注释反汇编显示demangled调用:

  │ │ 0000000000404310 <caller1()>: │ _ZL7caller1v(): │ push %rbp │ mov %rsp,%rbp | $0x30,%rsp | $0x0,-0x18(%rbp) │10: cmpq $0x3e8,-0x18(%rbp) │ ↓ jae 6f │ → callq my_really_big_function() │ lea -0x1c(%rbp),%rcx │ mov %eax,-0x1c(%rbp) 14.29 │ mov %rcx,-0x10(%rbp) │ mov -0x10(%rbp),%rcx │ lea -0x28(%rbp),%rcx │ mov $0x5,%eax │ mov %eax,%edx │ mov -0x18(%rbp),%rax │ xor %esi,%esi │ mov %rdx,-0x30(%rbp) │ mov %esi,%edx │ mov -0x30(%rbp),%rdi │ div %rdi 85.71 │ mov %rdx,-0x28(%rbp) │ mov %rcx,-0x8(%rbp) │ mov -0x8(%rbp),%rcx │ mov -0x18(%rbp),%rax │ add $0x1,%rax │ mov %rax,-0x18(%rbp) │ ↑ jmpq 10 │6f: add $0x30,%rsp │ pop %rbp │ ← retq 

系统信息:

  • Ubuntu 15.04 64位
  • 英特尔i5-6600k
  • perf 3.19.8-ckt6
  • 铿锵3.6.0-2ubuntu1

我在Ubuntu 15.10上遇到了同样的问题,我在这里找到了解决方案: https : //bugs.launchpad.net/ubuntu/+source/linux/+bug/1396654

这里是步骤:

 sudo apt-get install libiberty-dev binutils-dev mkdir ~/install cd ~/install apt-get source linux-tools-`uname -r` sudo apt-get build-dep linux-tools-`uname -r` cd linux-`uname -r | sed 's/-.*//'`/tools/perf make # now you should see the new "perf" executable here ./perf 

还应该有一些方法来创建一个新的linux-tools-common软件包,以真正将其集成到您的系统中。 现在要覆盖你的新的官方性能,只需设置你的路径:

 export PATH=~/install/linux-`uname -r | sed 's/-.*//'`/tools/perf:$PATH