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:
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root_type personal_info_list; |
因为要以protobuf做性能参考,列出protobuf的idl文件如下:
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//// FILE : tellist.proto |
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optional string name = 2; |
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optional gender_type gender = 4; |
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optional uint64 phone_num = 5; |
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message personal_info_list |
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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:
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测试环境:12Core Intel(R) Xeon(R) CPU E5-2620 0 @ 2.00GHz |
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total used free shared buffers cached |
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Mem: 66081944 65831100 250844 0 182240 46903452 |
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-/+ buffers/cache: 18745408 47336536 |
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Swap: 975864 724648 251216 |
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loop = 1000000, time diff = 14283ms |
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loop = 1000000, time diff = 14096ms |
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loop = 1000000, time diff = 14229ms |
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占用内存空间841Byte,平均运算时间42608ms / 3 = 14202.7ms |
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loop = 1000000, time diff = 11694ms |
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loop = 1000000, time diff = 11710ms |
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loop = 1000000, time diff = 11774ms |
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占用内存空间1712Byte,平均运算时间35178ms / 3 = 11726ms |
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测试环境:1 Core Intel(R) Core(TM) i5-3210M CPU @ 2.50GHz |
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total used free shared buffers cached |
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Mem: 753932 432672 321260 0 89236 258052 |
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-/+ buffers/cache: 85384 668548 |
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loop = 1000000, time diff = 12779ms |
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loop = 1000000, time diff = 13475ms |
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loop = 1000000, time diff = 12604ms |
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占用内存空间841Byte,平均运算时间38858ms / 3 = 12952.7ms |
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loop = 1000000, time diff = 9424ms |
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loop = 1000000, time diff = 9277ms |
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loop = 1000000, time diff = 9265ms |
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info vecotor size:37, its right size:37 |
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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。