TCMalloc优化MySQL、Nginx、Redis内存管理

Tcmalloc概述： TCMalloc (Thread-Caching Malloc)与标准glibc库的malloc实现一样的功能，但是TCMalloc在效率和速度效率都比标准malloc高很多。TCMalloc是google-perftools工具中的一个（gperftools四个工具分别是：TCMalloc、heap-checker、heap-profiler和

Tcmalloc概述：

TCMalloc(Thread-Caching Malloc)与标准glibc库的malloc实现一样的功能，但是TCMalloc在效率和速度效率都比标准malloc高很多。TCMalloc是google-perftools工具中的一个（gperftools四个工具分别是：TCMalloc、heap-checker、heap-profiler和cpu-profiler），这个工具是开源的，以源码形式发布。如果觉得自己维护一个内存分配器麻烦的话，可以考虑将TCMalloc静态库连接到你的程序中。使用的时候和glibc中的malloc调用方式一模一样。你需要做的只是把TCMalloc的动态库或者静态库连接进你的程序中，你就可以获得一个高效，快速，安全的内存分配器。

与标准的glibc库的malloc相比，TCMalloc在内存的分配效率和速度要高，可以在高并发的情况下很好的控制内存的使用，提高服务器的性能，降低负载。TCMalloc的实现原理和测试报告请见一篇文章：《TCMalloc：线程缓存的Malloc》

tcmalloc将内存请求分为两类，大对象请求和小对象请求，大对象为>=32K的对象。|
tcmalloc会为每个线程分配线程局部缓冲
对于小对象请求，可以直接从线程局部缓冲区获取，如果线程局部缓冲区没有空闲内存，则从central heap中一次性获取一连串小对象。
tcmalloc对于小内存，按8的整数次倍分配，对于大内存，按4K的整数次倍分配。
这样做有两个好处，一是分配的时候比较快。二是短期的收益比较大，分配的小内存至多浪费7个字节，大内存则4K
当某个线程缓存当缓存中所有对象的总共大小超过2MB的时候，会对他进行垃圾收集。垃圾收集阈值会自动根据线程数量的增加而减少，这样就不会因为程序有大量线程而过度浪费内存。

内存泄露检测
使用Tcmalloc的程序，用valgrind无法检测内存泄露，可以使用google-perftools提供的heap checker
使用方法：
export HEAPCHECK=TYPE
TYPE可以为：minimal、normal、strict、draconian

tcmalloc作为可选项已经添加到《lnmp最新源码一键安装包》

安装libunwind库：
如果系统是64位的需要先安装libunwind库，32位系统则不需要安装。

libunwind库为基于64位CPU和操作系统的程序提供了基本的堆栈辗转开解功能，其中包括用于输出堆栈跟踪的API用于以编程方式辗转开解堆栈的API以及支持C++异常处理机制的API。

<span>wget http</span><span>://</span><span>download</span><span>.</span><span>savannah</span><span>.</span><span>gnu</span><span>.</span><span>org</span><span>/</span><span>releases</span><span>/</span><span>libunwind</span><span>/</span><span>libunwind</span><span>-</span><span>1.1</span><span>.</span><span>tar</span><span>.</span><span>gztar zxf libunwind</span><span>-</span><span>1.1</span><span>.</span><span>tar</span><span>.</span><span>gzcd libunwind</span><span>-</span><span>1.1</span><span>CFLAGS</span><span>=-</span><span>fPIC </span><span>./</span><span>configuremake CFLAGS</span><span>=-</span><span>fPICmake CFLAGS</span><span>=-</span><span>fPIC installcd </span><span>../</span>

gperftools的安装：

<span>wget http</span><span>://</span><span>gperftools</span><span>.</span><span>googlecode</span><span>.</span><span>com</span><span>/</span><span>files</span><span>/</span><span>gperftools</span><span>-</span><span>2.1</span><span>.</span><span>tar</span><span>.</span><span>gztar xzf gperftools</span><span>-</span><span>2.1</span><span>.</span><span>tar</span><span>.</span><span>gzcd gperftools</span><span>-</span><span>2.1</span>

可以加入参数只编译tcmalloc（./configure –enable-minimal、–disable-cpu-profiler、–disable-heap-profiler、–disable-heap-checker、–disable-debugalloc），64位操作系统不安装libunwind也不会报错，注意生成的库文件是libtcmalloc_minimal.*
64位操作系统，如下

<span>./</span><span>configure </span>

32位系统，不需要安装libunwind，但是一定要添加–enable-frame-pointers参数，如下

<span>./</span><span>configure <p style="color:transparent">本文来源gao!daima.com搞$代!码网</p></span><span>--</span><span>enable</span><span>-</span><span>frame</span><span>-</span><span>pointers </span>

<span>make </span><span>&&</span><span> make install</span>

编译安装后，输入以下命令：

<span>echo </span><span>'/usr/local/lib'</span><span>></span><span>/</span><span>etc</span><span>/</span><span>ld</span><span>.</span><span>so</span><span>.</span><span>conf</span><span>.</span><span>d</span><span>/</span><span>local</span><span>.</span><span>confldconfig </span><span>#必须执行</span>

使用TCMalloc优化MySQL
MySQL 5.1静态编译方法，./configure预编译时假设下面参数

<span>--</span><span>with</span><span>-</span><span>mysqld</span><span>-</span><span>ldflags</span><span>=-</span><span>ltcmalloc</span>

MySQL 5.5静态编译方法，cmake预编译时加上下面参数

<span>-</span><span>DCMAKE_EXE_LINKER_FLAGS</span><span>=</span><span>"-ltcmalloc"</span><span>-</span><span>DWITH_SAFEMALLOC</span><span>=</span><span>OFF</span>

采用动态加载

<span>sed </span><span>-</span><span>i </span><span>'s@executing mysqld_safe@executing mysqld_safe\nexport LD_PRELOAD=/usr/local/lib/libtcmalloc.so@'</span><span>/</span><span>usr</span><span>/</span><span>local</span><span>/</span><span>mysql</span><span>/</span><span>bin</span><span>/</span><span>mysqld_safeservice mysqld restart</span>

验证加载tcmalloc在MySQL中是否生效，如下:

<span>lsof </span><span>-</span><span>n </span><span>|</span><span> grep tcmalloc</span>

使用TCMalloc优化Nginx
为了使nginx支持google-perftools，需要在安装过程中添加”–with-google_perftools_module”选项重新编译nginx。安装如下：

<span>cd lnmp</span><span>/</span><span>src</span><span>/</span><span>nginx</span><span>-</span><span>1.4</span><span>.</span><span>2</span><span>make clean</span><span>./</span><span>configure </span><span>--</span><span>prefix</span><span>=/</span><span>usr</span><span>/</span><span>local</span><span>/</span><span>nginx </span><span>--</span><span>user</span><span>=</span><span>www </span><span>--</span><span>group</span><span>=</span><span>www \</span><span>--</span><span>with</span><span>-</span><span>http_stub_status_module </span><span>--</span><span>with</span><span>-</span><span>http_ssl_module </span><span>--</span><span>with</span><span>-</span><span>http_flv_module \</span><span>--</span><span>with</span><span>-</span><span>http_gzip_static_module </span><span>--</span><span>with</span><span>-</span><span>google_perftools_modulemake </span><span>&&</span><span> make install</span>

为添加线程目录:

<span>mkdir </span><span>/</span><span>tmp</span><span>/</span><span>tcmallocchown </span><span>-</span><span>R www</span><span>.</span><span>www </span><span>/</span><span>tmp</span><span>/</span><span>tcmallocvi </span><span>/</span><span>usr</span><span>/</span><span>local</span><span>/</span><span>nginx</span><span>/</span><span>conf</span><span>/</span><span>nginx</span><span>.</span><span>conf </span><span>#pid下一行添加</span><span>google_perftools_profiles </span><span>/</span><span>tmp</span><span>/</span><span>tcmalloc</span><span>;</span>

验证tcmalloc是否在Nginx中生效

<span>lsof </span><span>-</span><span>n </span><span>|</span><span> grep tcmalloc</span>

每个线程（work_processes的值）会有一行记录。每个线程文件后面的数字值就是启动的nginx的pid值。

使用TCMalloc优化redis
注意：redis-2.4以上自带jemalloc，你不需要加任何参数，通过zmalloc.c源码中我们可以看到，Redis在编译时，会先判断是否使用tcmalloc，如果是，会用tcmalloc对应的函数替换掉标准的libc中的函数实现。其次会判断jemalloc是否使得，最后如果都没有使用才会用标准的libc中的内存管理函数。所以用tcmalloc优化请谨慎使用，这两着分配器碎片率相差不大，建议用自带jemalloc

<span>cd lnmp</span><span>/</span><span>src</span><span>/</span><span><span>redis</span></span><span>-</span><span>2.6</span><span>.</span><span>16</span><span>make USE_TCMALLOC</span><span>=</span><span>yes FORCE_LIBC_MALLOC</span><span>=</span><span>yes</span><span>/</span><span>bin</span><span>/</span><span>cp src</span><span>/{</span><span>redis</span><span>-</span><span>benchmark</span><span>,</span><span>redis</span><span>-</span><span>check</span><span>-</span><span>aof</span><span>,</span><span>redis</span><span>-</span><span>check</span><span>-</span><span>dump</span><span>,</span><span>redis</span><span>-</span><span>cli</span><span>,</span><span>redis</span><span>-</span><span>sentinel</span><span>,</span><span>redis</span><span>-</span><span>server</span><span>}</span><span>/</span><span>usr</span><span>/</span><span>local</span><span>/</span><span>redis</span><span>/</span><span>bin</span>

其他参考：

http://blog.gaodaima.com/chosen0ne/article/details/9338591

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