redis 性能调优

http://redis.io/topics/latency

http://stackoverflow.com/questions/16841469/redis-performance-tuning

http://www.oschina.net/translate/redis-latency-problems-troubleshooting

https://www.datadoghq.com/wp-content/uploads/2013/09/Understanding-the-Top-5-Redis-Performance-Metrics.pdf

expire源码分析

http://blog.sina.com.cn/s/blog_48c95a190101e5hv.html

http://in.sdo.com/?p=1688

http://www.cppblog.com/richbirdandy/archive/2011/11/29/161184.html