L1 cache reference ......................... 0.5 ns
Branch mispredict ............................ 5 ns on recent CPU
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 = 3 µs
Send 2K bytes over 1 Gbps network ....... 20,000 ns = 20 µs
SSD random read ........................ 150,000 ns = 150 µs
Read 1 MB sequentially from memory ..... 250,000 ns = 250 µs 4X memory
Round trip within same datacenter ...... 500,000 ns = 0.5 ms 20x datacenter roundtrip
Read 1 MB sequentially from SSD* ..... 1,000,000 ns = 1 ms 80x memory, 20X SSD
Disk seek ........................... 10,000,000 ns = 10 ms
Read 1 MB sequentially from disk .... 20,000,000 ns = 20 ms
Send packet CA->Netherlands->CA .... 150,000,000 ns = 150 ms
LTO4 tape seek/access time ...... 55.000.000.000 ns = 55 s

strings /dev/mem|less

Software developers using Windows have a fantastic process explorer, made by Mark Russinovich. Linux lacks such a process explorer tool. This projects aims (in the end) to be an equivalent process explorer for Linux.

Goal is to have the same functionality of the Windows process explorer under linux, or less if linux limits us.

(via links.zirko.me)