作为一个programmer你应该了解的latency

转载自：https://gist.github.com/jboner/2841832 Latency Comparison Numbers--------------------------L1 cache reference                            0.5 nsBranch mispredict                             5   nsL2 cache reference                            7   ns             14x L1 cacheMutex lock/unlock                            25   nsMain memory reference                       100   ns             20x L2 cache, 200x L1 cacheCompress 1K bytes with Zippy              3,000   nsSend 1K bytes over 1 Gbps network        10,000   ns    0.01 msRead 4K randomly from SSD*              150,000   ns    0.15 msRead 1 MB sequentially from memory      250,000   ns    0.25 msRound trip within same datacenter       500,000   ns    0.5  msRead 1 MB sequentially from SSD*      1,000,000   ns    1    ms  4X memoryDisk seek                            10,000,000   ns   10    ms  20x datacenter roundtripRead 1 MB sequentially from disk     20,000,000   ns   20    ms  80x memory, 20X SSDSend packet CA->Netherlands->CA     150,000,000   ns  150    ms Notes-----1 ns = 10-9 seconds1 ms = 10-3 seconds* Assuming ~1GB/sec SSD Credit------By Jeff Dean:               http://research.google.com/people/jeff/Originally by Peter Norvig: http://norvig.com/21-days.html#answers Contributions-------------Some updates from:                      https://gist.github.com/2843375Great 'humanized' comparison version:   https://gist.github.com/2843375Visual comparison chart:                http://i.imgur.com/k0t1e.pngNice animated presentation of the data: http://prezi.com/pdkvgys-r0y6/latency-numbers-for-programmers-web-development/   



   以下图片参考自：http://www.anandtech.com/show/4955/the-bulldozer-review-amd-fx8150-tested/6