elaatifi · August 6, 2014 10:41 · Aug 6, 2014
diff --git a/gistfile1.txt b/gistfile1.txt
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+Latency Comparison Numbers
+--------------------------
+L1 cache reference                            0.5 ns
+Branch mispredict                             5   ns
+L2 cache reference                            7   ns             14x L1 cache
+Mutex lock/unlock                            25   ns
+Main memory reference                       100   ns             20x L2 cache, 200x L1 cache
+Compress 1K bytes with Zippy              3,000   ns
+Send 1K bytes over 1 Gbps network        10,000   ns    0.01 ms
+Read 4K randomly from SSD*              150,000   ns    0.15 ms
+Read 1 MB sequentially from memory      250,000   ns    0.25 ms
+Round trip within same datacenter       500,000   ns    0.5  ms
+Read 1 MB sequentially from SSD*      1,000,000   ns    1    ms  4X memory
+Disk seek                            10,000,000   ns   10    ms  20x datacenter roundtrip
+Read 1 MB sequentially from disk     20,000,000   ns   20    ms  80x memory, 20X SSD
+Send packet CA->Netherlands->CA     150,000,000   ns  150    ms
+
+Notes
+-----
+1 ns = 10-9 seconds
+1 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/2843375
+Great 'humanized' comparison version:   https://gist.github.com/2843375
+Visual comparison chart:                http://i.imgur.com/k0t1e.png
+Nice animated presentation of the data: http://prezi.com/pdkvgys-r0y6/latency-numbers-for-programmers-web-development/