Latency Comparison Numbers

latency_comparison_numbers.txt

Latency Comparison Numbers
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execute typical instruction                  1   ns   1/1,000,000,000 sec                   
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       
Read 4K randomly from SSD*             150,000   ns   ~1GB/sec SSD
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   1 ms  ~1GB/sec SSD, 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
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1 ns = 10^-9 seconds
1 us = 10^-6 seconds = 1,000 ns
1 ms = 10^-3 seconds = 1,000 us = 1,000,000 ns