安装jemalloc

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apt install libjemalloc2

安装svg图片生成工具

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apt install graphviz gv

测试代码

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#include <iostream>
#include <string>
#include <vector>
#include <map>
#include <chrono>
#include <thread>

int main() {

    std::vector<int> vec;
    std::map<int, int> mp;
    std::string s;
    for (;;) {
        for (int i = 0; i < 1000; ++i) {
            vec.push_back(i);
            mp[rand()] = i;
            s += "xxxx";
            new char[4];
        }
        std::this_thread::sleep_for(std::chrono::microseconds(100));
    }

    return 0;
}

编译

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g++ -o test -g test.cpp

运行

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MALLOC_CONF=prof:true,lg_prof_interval:26 LD_PRELOAD=/usr/lib/x86_64-linux-gnu/libjemalloc.so.2 ./test

prof:true表示打开堆检测，lg_prof_interval:26使jemalloc开启prof并且每2^26字节(64M)大小进行一次dump

手动触发

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#include <jemalloc/jemalloc.h>

void menualTrigger() {
    static int heap_idx = 0;
    std::string heap_name = "exe" + std::to_string(heap_idx) + ".heap";
    const char* filename = heap_name.c_str();
    auto ret = mallctl("prof.dump", NULL, NULL, &filename, sizeof(const char*));
    heap_idx++;
}

g++ -ljemalloc

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MALLOC_CONF="prof:true" ./your_program

在合适的时候调用menualTrigger即可拍摄内存快照

生成内存泄露图

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jeprof --pdf a.out --base=jeprof.1646511.0.i0.heap  jeprof.1646511.100.i100.heap > result.pdf

–base表示基准堆，即第一次dump的堆，后面每次dump的堆都会和基准堆进行比较，从而找出内存泄露的函数