MASAKA

即使已经消亡,星光依然照耀我们

0%

常见的一些设备延迟

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 10,000 ns = 10 us
Send 1 KB bytes over 1 Gbps network 10,000 ns 10 us
Read 4 KB randomly from SSD* 150,000 ns = 150 us ~1GB/sec SSD
Read 1 MB sequentially from memory 250,000 ns = 250 us
Round trip within same datacenter 500,000 ns = 500 us
Read 1 MB sequentially from SSD* 1,000,000 ns=1,000 us=1 ms ~1GB/sec SSD, 4X memory
Disk seek 10,000,000 ns=10,000 us=10 ms 20x datacenter roundtrip
Read 1 MB sequentially from 1 Gbps 10,000,000 ns=10,000 us=10 ms 40x memory, 10X SSD
Read 1 MB sequentially from disk 30,000,000 ns=30,000 us=30 ms 120x memory, 30X SSD
Send packet CA->Netherlands->CA 150,000,000 ns=150,000 us=150 ms

Notes

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

欢迎关注我的其它发布渠道