FlatBuffers发布时，顺便也公布了它的性能数据，具体数据请见Benchmark。

    它的测试用例由以下数据构成"a set of about 10 objects containing an array, 4 strings, and a large variety of int/float scalar values of all sizes, meant to be representative of game data, e.g. a scene format."

   我感觉这样测试如同儿戏，便自己设计了一个测试用例，主要关注CPU计算时间和内存空间占用两个指标，参考对象是protobuf。

   测试用例为：序列化一个通讯录personal_info_list（table），通讯录可以认为是有每个人的信息(personal_info)的集合。每个人信息personal_info(table)有：个人id(uint)、名字(string)、年龄(byte)、性别(enum, byte)和电话号码(ulong)。本来我想用struct表示personal_info(table)，但是struct不允许有数组或string成员，无奈我用table描述它了。相应的idl文件如下：

////////////////////////////////////////////////////////// FILE     : tellist.fbs//// DESC     : basic message for msg-center//// AUTHOR   : v 0.1 written by Alex Stocks on June 22, 2014//// LICENCE  ://// MOD      :////////////////////////////////////////////////////////namespace as.tellist;enum GENDER_TYPE : byte{	MALE	= 0,	FEMALE	= 1,	OTHER	= 2}table personal_info{	id : uint;	name : string;	age : byte;	gender : GENDER_TYPE;	phone_num : ulong;}table personal_info_list{	info : [personal_info];}root_type personal_info_list;

   因为要以protobuf做性能参考，列出protobuf的idl文件如下：    

////////////////////////////////////////////////////////// FILE     : tellist.proto//// DESC     : basic message for msg-center//// AUTHOR   : v 0.1 written by Alex Stocks on June 22, 2014//// LICENCE  ://// MOD      :////////////////////////////////////////////////////////package as.tellist;enum gender_type{	MALE	= 0;	FEMALE	= 1;	OTHER	= 2;}message personal_info{	optional uint32			id = 1;	optional string			name = 2;	optional uint32			age = 3;	optional gender_type	gender = 4;	optional uint64			phone_num = 5;}message personal_info_list{	repeated personal_info	info = 1;}

    在内存中构造37个personal_info对象，并序列化之，重复这个过程100万次。

    测试结果如下：

测试环境：12Core Intel(R) Xeon(R) CPU E5-2620 0 @ 2.00GHz free             total       used       free     shared    buffers     cachedMem:      66081944   65831100     250844          0     182240   46903452-/+ buffers/cache:   18745408   47336536Swap:       975864     724648     251216protobuf三次测试结果：./bin/tellist_test loop = 1000000, time diff = 14283msbuf size:841bin/tellist_test loop = 1000000, time diff = 14096msbuf size:841bin/tellist_test loop = 1000000, time diff = 14229msbuf size:841占用内存空间841Byte，平均运算时间42608ms / 3 = 14202.7msflatbuffers三次测试结果：bin/tellist_test loop = 1000000, time diff = 11694msbuf size:1712 bin/tellist_test loop = 1000000, time diff = 11710msbuf size:1712bin/tellist_test loop = 1000000, time diff = 11774msbuf size:1712占用内存空间1712Byte，平均运算时间35178ms / 3 = 11726ms测试环境：1 Core Intel(R) Core(TM) i5-3210M CPU @ 2.50GHzMEM             total       used       free     shared    buffers     cachedMem:        753932     432672     321260          0      89236     258052-/+ buffers/cache:      85384     668548Swap:      1324028          0    1324028protobuf三次测试结果：bin/tellist_test loop = 1000000, time diff = 12779msbuf size:841bin/tellist_test loop = 1000000, time diff = 13475msbuf size:841bin/tellist_test loop = 1000000, time diff = 12604msbuf size:841占用内存空间841Byte，平均运算时间38858ms / 3 = 12952.7msflatbuffers三次测试结果：bin/tellist_test loop = 1000000, time diff = 9424msbuf size:1712 bin/tellist_test loop = 1000000, time diff = 9277msbuf size:1712bin/tellist_test loop = 1000000, time diff = 9265msbuf size:1712info vecotor size:37, its right size:37占用内存空间1712Byte，平均运算时间28036ms / 3 = 9345ms

    从以上数据看出，在内存空间占用这个指标上，FlatBuffers占用的内存空间比protobuf多了两倍，而二者的cpu计算时间虽然相差3000ms左右，但考虑到测试用了100万次，二者每次计算时间几乎没有差别。

    从以上测试数据来看，FlatBuffers的性能并不如它吹嘘的那么好，个人稍有点失望。FB大量使用了C++11的语法，其从idl生成的代码接口也不如protubuf友好。不过相比使用protobuf时的一堆头文件和占18M之多的lib库，FlatBuffers仅仅一个"flatbuffers/flatbuffers.h"就足够了。

    测试程序已经上传到百度网盘，点击这个链接即可下载。欢迎各位的批评意见。