Redis和Memcached在Ruby上的性能评测（1）——写入性能

因为memcached只支持String数据类型，所以本文只比较String，redis支持的其他数据类型不做评测，另外关闭了redis持久化特性！因为redis的持久化是另起后台任务进行，所以数据量小的时候不会对测试结果有明显影响。

测试环境：

引用

REDHAT6.0 x86_64
Ruby Enterprise Edition version 1.8.7-2010.02
memcached 1.4.4
redis-2.4.6
Gems:
memcached(1.3.5)
hiredis (0.4.4)

相关配置：
memcached：-m 1024 -c 1024 -t 8
内存：1G，并发连接：1024，线程数：8

redis：默认配置，其中持久化数据部分关闭
loglevel warning
#save 900 1
#save 300 10
#save 60 10000
rdbcompression yes

测试方式：随即生成1000byte内的字符串，写入10万次。
memcached代码：

require 'rubygems'
require 'memcached'
@cache = Memcached.new('localhost:11211')
100000.times do |i|
  @cache.set "Test/#{i}", '0'*rand(1000)
end

redis测试代码：

require 'rubygems'
require 'hiredis'
@cache = Hiredis::Connection.new
@cache.connect("127.0.0.1", 6379)
100000.times do |i|
  @cache.write ['SET', "Test/#{i}", '0'*rand(1000)]
  @cache.read
end

测试结果：

													real	user	sys
memcached	1x SET pipeline		10000 times		0.937s	0.305s	0.376s
redis		1x SET pipeline		10000 times		1.218s	0.517s	0.318s
						
memcached	10x SET pipeline	10000 times		1.954s	3.311s	1.794s	
redis		10x SET pipeline	10000 times		3.578s	5.610s	2.229s		
						
memcached	20x SET pipeline	10000 times		3.724s	6.789s	3.547s	
redis		20x SET pipeline	10000 times		7.024s	11.409s	4.259s	

memcached	1x SET pipeline		100000 times		8.434s	2.849s	3.165s
redis		1x SET pipeline		100000 times		10.088s	3.315s	2.979s
						
memcached	10x SET pipeline	100000 times		15.823s	21.094s	14.900s	
redis		10x SET pipeline	100000 times		26.971s	20.364s	14.673s		
						
memcached	20x SET pipeline	100000 times		28.992s	42.706s	29.173s	
redis		20x SET pipeline	100000 times		50.189s	40.969s	27.939s	

memcached	1x SET pipeline		1000000 times		1m16.988s	26.652s	27.189s
redis		1x SET pipeline		1000000 times		1m39.096s	25.127s	28.373s
						
memcached	10x SET pipeline	1000000 times		2m30.850s	3m22.393s	2m26.716s
redis		10x SET pipeline	1000000 times		4m19.509s	2m46.179s	2m18.871s
	
memcached	20x SET pipeline	1000000 times		6m22.883s	9m2.995s	6m5.845s	
redis		20x SET pipeline	1000000 times		12m55.556s	9m6.064s	6m56.633s

结论：
1、memcached的写入性能还是明显要高于redis，特别是多并发的时候，优势更明显！
2、redis server的占用一般在50％左右，memcached server的CPU占用150%左右
3、从总体CPU占用率上来说，redis的优势很明显，4核CPU的使用率没有超过20％，而memcached的CPU一直在50％左右。