gperftools编译与使用

参考   http://ju.outofmemory.cn/entry/24487

编译gperftools

编译并安装libunwind，命令如下所示。注意这个过程很关键，否者heap profiler产生的数据文件都会是空的。我和小师妹在这个问题上纠结了好久，剑豪也遇到过这个问题。幸好今天听亚夫讲到libunwind，才最终解决了这个问题。

  1727  ./configure --prefix=/home/liminghao/tools/libunwind/ CFLAGS=-U_FORTRIFY_SOURCE

 1728  make

 1729  make install 

  1753  ./configure --prefix=/home/liminghao/tools/gperftools LDFLAGS=-L/home/liminghao/tools/libunwind/lib CPPFLAGS=-I/home/liminghao/tools/libunwind/include

 1754  make

 1755  make install 

使用heap profiler

实例代码

#include <iostream>

using namespace std;

const uint32_t len = 102400;

char* foo()
{
char* p = new char[len];
memset(p, 0, len);

return p;
}

char* bar()
{
char* p = new char[len];
memset(p, 0, len);

return p;
}

int main(int argc, const char *argv[])
{
for (int i = 0; i < 1000; i++) {
char* f = foo();
memcpy(f, "abc", 3);

char* b = bar();
memcpy(b, "abc", 3);
}

return 0;
}

编译命令

g++ -g google_perf_test.cpp -o google_perf_test

运行命令

$ env LD_PRELOAD="/home/henshao/googleperf_install/lib/libtcmalloc.so" HEAPPROFILE="./perf_log/perf_leak.log" ./google_perf_test
Starting tracking the heap
Dumping heap profile to ./perf_log/perf_leak.log.0001.heap (100 MB currently in use)
Dumping heap profile to ./perf_log/perf_leak.log.0002.heap (Exiting)

分析结果

从下面的结果可以看出，foo和bar两个函数分别申请了100MB的内存。

$ pprof --text google_perf_test perf_log/perf_leak.log.0003.heap
Using local file google_perf_test.
Using local file perf_log/perf_leak.log.0003.heap.
Total: 200.0 MB
.0  50.0%  50.0%    100.0  50.0% bar
.0  50.0% 100.0%    100.0  50.0% foo
.0   0.0% 100.0%      0.0   0.0% PrintStats
.0   0.0% 100.0%      0.0   0.0% std::string::_Rep::_S_create
.0   0.0% 100.0%      0.0   0.0% __static_initialization_and_destruction_0@29a30
.0   0.0% 100.0%      0.0   0.0% 0x00002b71bca8adcf
.0   0.0% 100.0%      0.0   0.0% __cxa_finalize
.0   0.0% 100.0%      0.0   0.0% __do_global_ctors_aux
.0   0.0% 100.0%      0.0   0.0% __do_global_dtors_aux
.0   0.0% 100.0%    200.0 100.0% __libc_start_main
.0   0.0% 100.0%      0.0   0.0% _fini
.0   0.0% 100.0%      0.0   0.0% _init
.0   0.0% 100.0%    200.0 100.0% _start
.0   0.0% 100.0%      0.0   0.0% exit
.0   0.0% 100.0%    200.0 100.0% main
.0   0.0% 100.0%      0.0   0.0% std::basic_string::basic_string
.0   0.0% 100.0%      0.0   0.0% std::string::_S_copy_chars

小帮助

The first column contains the direct memory use in MB.
The fourth column contains memory use by the procedure and all of its callees.
The second and fifth columns are just percentage representations of the numbers in the first and fourth columns.
The third column is a cumulative sum of the second column (i.e., the kth entry in the third column is the sum of the first k entries in the second column.)