The Computer Latency Calendar
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I recently saw this Gist and Interactive Page, so I thought it would be cool to update it for the 2020s. This can serve as a visualization of how fast a modern computer is.
How to read this calendar
Imagine 1 CPU cycle took 1 second. Compared to that, A modern 4.0 GHz CPU has a CPU cycle of 0.25 ns approx. That's 4,000,000,000 times difference. Now, imagine how that CPU would feel one second in real life.
Action | Physical Time | CPU Time |
---|---|---|
1 CPU Cycle | 0.25ns | 1 second |
L1 cache reference | 1ns | 4 seconds |
Branch mispredict | 3ns | 12 seconds |
L2 cache reference | 4ns | 16 seconds |
Mutex lock | 17ns | 68 seconds |
Send 2KB | 44ns | 2.93 minutes |
Main memory reference | 100ns | 6.67 minutes |
Compress 1KB | 2μs | 2.22 hours |
Read 1MB from memory | 3μs | 3.33 hours |
SSD random read | 16μs | 17.78 hours |
Read 1MB from SSD | 49μs | 2.27 days |
Round trip in the same data center | 500μs | 23.15 days |
Read 1MB from the disk | 825μs | 38.20 days |
Disk seek | 2ms | 92.60 days |
Packet roundtrip from California to Seoul | 200ms | 25.35 years |
OS virtualization reboot | 5s | 633 years |
SCSI command timeout | 30s | 3,802 years |
Hardware virtualization reboot | 40s | 5,070 years |
Physical system reboot | 5m | 38,026 years |