[转] 利用jemalloc分析内存泄漏

from: https://blog.intzero.net/tools/jemalloc.html

Jemalloc 不仅实现了一种通用的malloc, 还能利用它来做内存分析和监控/调优等.

这里介绍如何利用jemalloc来检测内存泄漏问题. 并且利用LD_PRELOAD环境变量, 可以做到不需要源代码, 将jemalloc库嵌入到可执行程序中, 从而用jemalloc去malloc内存, 并进行管理. 也就是说, 每当程序中调用malloc/new时, 实际调用的是jemalloc里实现的函数.

Install

从releases获取jemalloc最新版.

参考: https://github.com/jemalloc/jemalloc/blob/dev/INSTALL.md

cd ~/jemalloc_test
wget https://github.com/jemalloc/jemalloc/releases/download/5.1.0/jemalloc-5.1.0.tar.bz2
tar zxvf jemalloc-5.1.0.tar.bz2
cd jemalloc-5.1.0
./configure --prefix=/home/intzero/jemalloc_test/jemalloc_install # 我这里装在自己目录下 make make install export PATH=/home/intzero/jemalloc_test/jemalloc_install/bin:$PATH

Getting Started

参考: https://github.com/jemalloc/jemalloc/wiki/Getting-Started

有几种方式将jemalloc整合到你的程序中.

一种是在源代码中加入jemalloc代码, 在build代码时嵌入.
另外一种是利用LD_PRELOAD环境变量, 在程序运行时就能嵌入, 不需要源代码.

另外可以通过 MALLOC_CONF环境变量来调整jemalloc.

写个demo测试一下.

vi main.cpp

#include <stdlib.h>
#include <iostream> #include <jemalloc/jemalloc.h> using namespace std; void do_something(size_t i) { // Leak some memory. int *p = new int[i]; // or malloc(i * 4); } int main(int argc, char **argv) { for (size_t i = 1; i <= 1000; i++) { do_something(i); } cout << "jemalloc test." << endl; // Dump allocator statistics to stderr. malloc_stats_print(NULL, NULL, NULL); return 0; }

运行:

$ g++ main.cpp -o main -I`jemalloc-config --includedir` -L`jemalloc-config --libdir` -Wl,-rpath,`jemalloc-config --libdir` -ljemalloc `jemalloc-config --libs` $ ./main

可看到打印出来的内存信息.

Leak Checking

vi main.cpp

#include <stdlib.h>
#include <iostream> using namespace std; void do_something(size_t i) { // Leak some memory. int *p = new int[i]; // or malloc(i * 4); } int main(int argc, char **argv) { for (size_t i = 1; i <= 1000; i++) { do_something(i); } cout << "jemalloc test." << endl; return 0; }

运行:

$ g++ main.cpp -o main
$ MALLOC_CONF=prof_leak:true,lg_prof_sample:0,prof_final:true LD_PRELOAD=/home/intzero/jemalloc_test/jemalloc_install/lib/libjemalloc.so.2 ./main

上面这条命令会执行./main, 并将jemalloc提前加载进去.

程序退出之后, 会生成类似jeprof.37252.0.f.heap的文件. 查看详细信息:

$ jeprof --show_bytes `which ./main` jeprof.37252.0.f.heap Using local file jeprof.37252.0.f.heap. Welcome to jeprof! For help, type 'help'. (jeprof) top Total: 2173680 B 2173680 100.0% 100.0% 2173680 100.0% 0x00007f8f2f7d7ac0 0 0.0% 100.0% 2173680 100.0% 0x00007f8f2e5b1b13 0 0.0% 100.0% 2173680 100.0% 0x00007f8f2f788581 0 0.0% 100.0% 2173680 100.0% 0x00007f8f2f7e93a0 0 0.0% 100.0% 2173680 100.0% _start 0 0.0% 100.0% 2173680 100.0% do_something 0 0.0% 100.0% 2173680 100.0% main (jeprof)

还可以生成call graph的PDF文件:

jeprof --show_bytes --pdf `which ./main` jeprof.37252.0.f.heap > w.pdf

转载于:https://www.cnblogs.com/Arborday/p/10973502.html