[quality] 01 - gpertools: measure each function

做算法，不懂性能分析，无颜见父老乡亲。

Software optimization resources【非常棒的资源博客，牛的不要不要的】

 

命令行步骤：

jeff@lolo-id:123$ g++ prof_test.cpp -o output -std=c++11 -lprofiler
jeff@lolo-id:123$ LD_PRELOAD=/usr/lib/libprofiler.so CPUPROFILE=p.prof CPUPROFILE_FREQUENCY=1000  ./output 10
PROFILE: interrupts/evictions/bytes = 695/174/8632
-------------------------------------------------------------------------------------------------------------
jeff@lolo-id:123$ pprof --callgrind ./output p.prof > p.txt
perl: warning: Setting locale failed.
perl: warning: Please check that your locale settings:
    LANGUAGE = "en_AU:en",
    LC_ALL = (unset),
    LANG = "zh_CN.GBK"
    are supported and installed on your system.
perl: warning: Falling back to the standard locale ("C").
Using local file ./output.
Using local file p.prof.
jeff@lolo-id:123$ kcachegrind p.txt&

-------------------------------------------------------------------------------------------------------------
pprof --pdf ./output p.prof > MyProfile.pdf
# create pdf to show the time cost distribution.
# https://www.ibm.com/developerworks/cn/linux/l-cn-googleperf/index.html

 

 

示范代码：

#include<gperftools/profiler.h>
#include<iostream>
#include<string>

void foo(int x){
    while(x>0){
        for(int i=0;i<10000000;++i);
        --x;
    }
}

void goo(int x){
    foo(x);
}

int main(int argc, char* argv[])
{
    int x = 100;
    goo(x);
    ProfilerStart("cpu.profile");
    foo(x);
    ProfilerStop();
    return 0;
}