Linux c++上常用内存泄露检测工具有valgrind, Rational purify。Valgrind免费。Valgrind 可以在 32 位或 64 位 PowerPC/Linux 内核上工作。
Valgrind工具包包含多个工具，如Memcheck,Cachegrind,Helgrind, Callgrind，Massif。下面分别介绍个工具的作用：
Memcheck 工具主要检查下面的程序错误：
• 使用未初始化的内存 (Use of uninitialised memory)
• 使用已经释放了的内存 (Reading/writing memory after it has been free’d)
• 使用超过 malloc分配的内存空间(Reading/writing off the end of malloc’d blocks)
• 对堆栈的非法访问 (Reading/writing inappropriate areas on the stack)
• 申请的空间是否有释放 (Memory leaks – where pointers to malloc’d blocks are lost forever)
• malloc/free/new/delete申请和释放内存的匹配(Mismatched use of malloc/new/new [] vs free/delete/delete [])
• src和dst的重叠(Overlapping src and dst pointers in memcpy() and related functions)
Valgrind不检查静态分配数组的使用情况。
Valgrind占用了更多的内存--可达两倍于你程序的正常使用量。如果你用Valgrind来检测使用大量内存的程序就会遇到问题，它可能会用很长的时间来运行测试
2.1. 下载安装
http://www.valgrind.org
安装
./configure;make;make install
2.2. 编译程序
被检测程序加入 –g   -fno-inline 编译选项保留调试信息。

2.3. 内存泄露检测
$ valgrind --leak-check=full --show-reachable=yes --trace-children=yes    ./iquery   -f ../conf/se.conf_forum -t   ~/eragon/forum_thread_data/f.log -NT   -cache 0
其中--leak-check=full 指的是完全检查内存泄漏，--show-reachable=yes是显示内存泄漏的地点，--trace-children=yes是跟入子进程。当程序正常退出的时候valgrind自然会输出内存泄漏的信息。

==4591== 
==4591== Thread 1:
==4591== Conditional jump or move depends on uninitialised value(s)
==4591== at 0x805687B: main (TestQuery.cpp:478)
==4591== 
==4591== Conditional jump or move depends on uninitialised value(s)
==4591== at 0x8056894: main (TestQuery.cpp:478)
==4591== 
==4591== Conditional jump or move depends on uninitialised value(s)
==4591== at 0x80568AD: main (TestQuery.cpp:478)
==4591== Warning: set address range perms: large range 215212032 (noaccess)
==4591== Warning: set address range perms: large range 125145088 (noaccess)
==4591== 
==4591== ERROR SUMMARY: 6 errors from 4 contexts (suppressed: 18 from 1)
==4591== malloc/free: in use at exit: 496 bytes in 2 blocks.
==4591== malloc/free: 928,605 allocs, 928,603 frees, 2,514,165,074 bytes allocated.
==4591== For counts of detected errors, rerun with: -v
==4591== searching for pointers to 2 not-freed blocks.
==4591== checked 10,260,564 bytes.
==4591== 
==4591== 
==4591== 144 bytes in 1 blocks are possibly lost in loss record 1 of 2
==4591== at 0x4005906: calloc (vg_replace_malloc.c:279)
==4591== by 0xB3671A: _dl_allocate_tls (in /lib/ld-2.3.4.so)
==4591== by 0xD9491E: pthread_create@@GLIBC_2.1 (in /lib/tls/libpthread-2.3.4.so)
==4591== by 0x8200C66: public_unit::CThread::start(void*) (Thread.cpp:25)
==4591== by 0x80567C3: main (TestQuery.cpp:473)
==4591== 
==4591== 
==4591== 352 bytes in 1 blocks are still reachable in loss record 2 of 2
==4591== at 0x40044F6: malloc (vg_replace_malloc.c:149)
==4591== by 0xB9905E: __fopen_internal (in /lib/tls/libc-2.3.4.so)
==4591== by 0xB9911C: fopen@@GLIBC_2.1 (in /lib/tls/libc-2.3.4.so)
==4591== by 0x805940C: CSearchThread::run(void*) (TestQuery.cpp:363)
==4591== by 0x8200D09: public_unit::CThread::thread_func(void*) (Thread.cpp:44)
==4591== by 0xD94370: start_thread (in /lib/tls/libpthread-2.3.4.so)
==4591== by 0xC0DFFD: clone (in /lib/tls/libc-2.3.4.so)
==4591== 
==4591== LEAK SUMMARY:
==4591== definitely lost: 0 bytes in 0 blocks.
==4591==    possibly lost: 144 bytes in 1 blocks.
==4591== still reachable: 352 bytes in 1 blocks.
==4591==       suppressed: 0 bytes in 0 blocks.

关键字在：ERROR SUMMARY, LEAK SUMMARY
"definitely lost" means your program is leaking memory -- fix it!
"possibly lost" means your program is probably leaking memory, unless you're doing funny things with pointers.
"still reachable" means your program is probably ok -- it didn't free some memory it could have. This is quite common and often reasonable. Don't use --show-reachable=yes if you don't want to see these reports.
"suppressed" means that a leak error has been suppressed. There are some suppressions in the default suppression files. You can ignore suppressed errors

另外一种方式，激活加载调试器
gcc -Wall -g   -pg -o get_XMLDOC   get_XMLDOC.c
$ valgrind --db-attach=yes   --leak-check=full    ./get_XMLDOC ~/eragon/data/offer_gb.xml   1.xml   10
==8956== Memcheck, a memory error detector.
==8956== Copyright (C) 2002-2006, and GNU GPL'd, by Julian Seward et al.
==8956== Using LibVEX rev 1606, a library for dynamic binary translation.
==8956== Copyright (C) 2004-2006, and GNU GPL'd, by OpenWorks LLP.
==8956== Using valgrind-3.2.0, a dynamic binary instrumentation framework.
==8956== Copyright (C) 2000-2006, and GNU GPL'd, by Julian Seward et al.
==8956== For more details, rerun with: -v
==8956== 
==8956== 
==8956== ---- Attach to debugger ? --- [Return/N/n/Y/y/C/c] ---- 
==8956== 
==8956== ERROR SUMMARY: 0 errors from 0 contexts (suppressed: 12 from 1)
==8956== malloc/free: in use at exit: 1,953 bytes in 2 blocks.
==8956== malloc/free: 4 allocs, 2 frees, 2,657 bytes allocated.
==8956== For counts of detected errors, rerun with: -v
==8956== searching for pointers to 2 not-freed blocks.
==8956== checked 52,840 bytes.
==8956== 
==8956== 1 bytes in 1 blocks are definitely lost in loss record 1 of 2
==8956== at 0x40044F6: malloc (vg_replace_malloc.c:149)
==8956== by 0x80488C0: main (get_XMLDOC.c:38)
==8956== 
==8956== LEAK SUMMARY:
==8956== definitely lost: 1 bytes in 1 blocks.
==8956==    possibly lost: 0 bytes in 0 blocks.
==8956== still reachable: 1,952 bytes in 1 blocks.
==8956==       suppressed: 0 bytes in 0 blocks.
==8956== Reachable blocks (those to which a pointer was found) are not shown.
==8956== To see them, rerun with: --show-reachable=yes
Profiling timer expired

2.4. 检查性能瓶颈
$valgrind --tool=callgrind ./iquery   -f ../conf/se.conf_forum -s "forum_thread?q=mp4"
…
==4607== 
==4607== Events : Ir
==4607== Collected : 251772397
==4607== 
==4607== I refs:    251,772,397

4607为进程号。
$ ll
-rw-------   1 search search 712159   7月   9 22:31 callgrind.out.4607
$ callgrind_annotate --auto=yes   callgrind.out.4607
WARNING: header line 2 malformed, ignoring
line: 'creator: callgrind-3.2.0'
--------------------------------------------------------------------------------
I1 cache: 
D1 cache: 
L2 cache: 
Timerange: Basic block 0 - 46942078
Trigger: Program termination
Profiled target:   ./iquery -f ../conf/se.conf_forum -s forum_thread?q=mp4 (PID 4607, part 1)
Events recorded:   Ir
Events shown:     Ir
Event sort order: Ir
Thresholds:    99
Include dirs:    
User annotated: 
Auto-annotation:   on

--------------------------------------------------------------------------------
      Ir 
--------------------------------------------------------------------------------
251,772,397   PROGRAM TOTALS

--------------------------------------------------------------------------------
       Ir   file:function
--------------------------------------------------------------------------------
54,769,656   ???:__mcount_internal [/lib/tls/libc-2.3.4.so]
26,418,450   GBKNormalString.cpp:dictionary::CGBKNormalString::initNormalChars() [/home/search/eragon_yb/bin/iquery]
22,820,690   ???:mcount [/lib/tls/libc-2.3.4.so]
11,559,615   GBKNormalString.cpp:dictionary::CGBKNormalString::initCharKinds() [/home/search/eragon_yb/bin/iquery]

更多说明参考：
http://www-128.ibm.com/developerworks/cn/linux/l-pow-debug/

2.5. cache测试
参考：http://www.wangcong.org/articles/valgrind.html
[search@alitest146 /home/search/eragon_yb/bin]
$ valgrind --tool=cachegrind   ./iquery -f ../conf/se.conf_forum -s "forum_thread?q=mp3"
==8742== 
==8742== I refs:    267,968,791
==8742== I1   misses:       98,845
==8742== L2i misses:       13,382
==8742== I1   miss rate:        0.03%
==8742== L2i miss rate:        0.00%
==8742== 
==8742== D refs:    182,288,669   (120,222,370 rd + 62,066,299 wr)
==8742== D1   misses:        962,816   ( 537,889 rd + 424,927 wr)
==8742== L2d misses:        707,813   ( 340,925 rd + 366,888 wr)
==8742== D1   miss rate:       0.5% (        0.4% +        0.6%   )
==8742== L2d miss rate:       0.3% (        0.2% +        0.5%   )
==8742== 
==8742== L2 refs:       1,061,661   ( 636,734 rd + 424,927 wr)
==8742== L2 misses:       721,195   ( 354,307 rd + 366,888 wr)
==8742== L2 miss rate:       0.1% (        0.0% +        0.5%   )

上面的是指令缓存，I1和L2i缓存，的访问信息，包括总的访问次数，丢失次数，丢失率。
中间的是数据缓存，D1和L2d缓存，的访问的相关信息，下面的L2缓存单独的信息。Cachegrind也生成一个文件，名为 cachegrind.out.pid，可以通过cg_annotate来读取。输出是一个更详细的列表。Massif的使用和cachegrind类 似，不过它也会生成一个名为massif.pid.ps的PostScript文件，里面只有一幅描述堆栈使用状况的彩图。

[search@alitest146 /home/search/Isearchv3_Script_yb/tools]
$ ll   cachegrind.out*
-rw-------   1 search search   7283 Jul 11 11:21 cachegrind.out. 8633

$   cg_annotate   --8633   --auto=yes   ~/isearch_yb/src/test/core/TestQuery.cpp                                                    
--------------------------------------------------------------------------------
I1 cache:       16384 B, 32 B, 8-way associative
D1 cache:       16384 B, 64 B, 8-way associative
L2 cache:       2097152 B, 64 B, 8-way associative
Command:       ./iquery -f ../conf/se.conf_forum -s forum_thread?q=mp3
Data file:        cachegrind.out.8633
Events recorded:   Ir I1mr I2mr Dr D1mr D2mr Dw D1mw D2mw
Events shown:     Ir I1mr I2mr Dr D1mr D2mr Dw D1mw D2mw
Event sort order: Ir I1mr I2mr Dr D1mr D2mr Dw D1mw D2mw
Thresholds:    99 0 0 0 0 0 0 0 0
Include dirs:    
User annotated: /home/search/isearch_yb/src/test/core/TestQuery.cpp
Auto-annotation:   on

--------------------------------------------------------------------------------
      Ir I1mr I2mr       Dr D1mr D2mr       Dw D1mw D2mw 
--------------------------------------------------------------------------------
267,968,791 98,845 13,395 120,222,370 537,889 340,938 62,066,299 424,927 366,883   PROGRAM TOTALS

--------------------------------------------------------------------------------
       Ir   I1mr   I2mr       Dr D1mr D2mr       Dw D1mw D2mw   file:function
--------------------------------------------------------------------------------
56,779,152 28     6 14,194,788    82    3 14,194,788    34    13   ???:__mcount_internal
26,418,450 108 54 12,868,530   22,710 3,028   1,943,010   79,943   30,480   GBKNormalString.cpp:dictionary::CGBKNormalString::initNormalChars()

……
-- User-annotated source: get_XMLDOC.c
--------------------------------------------------------------------------------
Ir I1mr I2mr Dr D1mr D2mr Dw D1mw D2mw

. . .     . . .     . . .   #include "stdio.h"
    . . .     . . .     . . .   #define LINE_MAX_LEN   10240
    . . .     . . .     . . .   //get part of   xml
    . . .     . . .     . . .   main(int argc,char *argv[])
10 1 1     0 0 0     1 0 0 {
    . . .     . . .     . . .    FILE *fp;
    1 0 0     0 0 0     1 0 0    FILE *fpDst =NULL;
    . . .     . . .     . . .    
    8 1 0     0 0 0     4 1 1    char content[LINE_MAX_LEN+1]={0};
    . . .     . . .     . . .    int   inumOfdocs;
    1 0 0     0 0 0     1 0 0    int   currentdocs=0;
    1 1 1     0 0 0     1 0 0    int   isDocBegin = 0;    
    1 0 0     0 0 0     1 0 0    int   isDocEnd = 0;
    . . .     . . .     . . .  
    2 0 0     1 0 0     0 0 0    if (argc < 4)
    . . .     . . .     . . .    {
    . . .     . . .     . . .        printf("usage: get_XMLDOC srcxml dstxml   numOfdocs\n");
    . . .     . . .     . . .        exit(1);
    . . .     . . .     . . .    }          
    . . .     . . .     . . .    
    7 2 1     2 0 0     3 0 0    inumOfdocs = atoi(argv[3]);
    2 0 0     1 0 0     0 0 0    if (inumOfdocs <=0 )