← Prasad Ekke

Latency Comparison Numbers (~2012)

How long common operations take on a computer, from a CPU cache hit to a packet crossing the Atlantic and back. Each bar sits on the same logarithmic scale, so every gridline is ten times the one before.

Nanoseconds Microseconds Milliseconds
L1 cache reference
0.5 ns
Branch mispredict
5 ns
L2 cache reference14x L1 cache
7 ns
Mutex lock/unlock
25 ns
Main memory reference20x L2 cache, 200x L1 cache
100 ns
Compress 1K bytes with Zippy
3 µs3,000 ns
Send 1K bytes over 1 Gbps network
10 µs10,000 ns
Read 4K randomly from SSD*~1GB/sec SSD
150 µs150,000 ns
Read 1 MB sequentially from memory
250 µs250,000 ns
Round trip within same datacenter
500 µs500,000 ns
Read 1 MB sequentially from SSD*~1GB/sec SSD, 4X memory
1 ms1,000,000 ns
Disk seek20x datacenter roundtrip
10 ms10,000,000 ns
Read 1 MB sequentially from disk80x memory, 20X SSD
20 ms20,000,000 ns
Send packet CA→Netherlands→CA
150 ms150,000,000 ns

Notes

1 ns = 10−9 seconds 1 µs = 10−6 seconds = 1,000 ns 1 ms = 10−3 seconds = 1,000 µs = 1,000,000 ns

Credit

Contributions