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pmorch/latency.markdown

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Last active August 29, 2018 18:42
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Latency numbers every programmer should know
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latency.markdown

Latency numbers every programmer should know

L1 cache reference ......................... 0.5 ns
Branch mispredict ............................ 5 ns
L2 cache reference ........................... 7 ns
Mutex lock/unlock ........................... 25 ns
Main memory reference ...................... 100 ns             
Compress 1K bytes with Zippy ............. 3,000 ns
Send 2K bytes over 1 Gbps network ....... 20,000 ns
SSD random read ........................ 150,000 ns
Read 1 MB sequentially from memory ..... 250,000 ns
Round trip within same datacenter ...... 500,000 ns
Read 1 MB sequentially from SSD* ..... 1,000,000 ns
Disk seek ........................... 10,000,000 ns
Read 1 MB sequentially from disk .... 20,000,000 ns
Send packet CA->Netherlands->CA .... 150,000,000 ns

Assuming ~1GB/sec SSD

Data by Jeff Dean

Originally by Peter Norvig

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