Latency numbers every programmer should know

latency.txt

"Magic" Numbers

Operation	Time (us)	Source
L1 cache reference	0.0005	2,3
Execute typical instruction	0.0010	2,3
Branch mispredict 	0.0050	2,3
Propagation delay in fiber-optic cable, per meter	0.0050	5
L2 cache reference 	0.0070	2,3
Mutex lock/unlock (uncontested)	0.0250	2,3
Decode FAST message	0.0500	5
Main memory reference 	0.1000	2,3
One-way message send (kernel-bypass w/Infiniband & RDMA)	1.0000	5
Serialization delay (1500 bytes) ? 10Gb Ethernet	1.2000	5
Thread context switch in Linux (best case)	1.3200	6
Process context switch in Linux (best case)	1.5000	6
One-way message send (kernel-bypass w/10Gb & RDMA)	2.0000	5
Compress 1K bytes w/ cheap algorithm 	3.0000	3
One-way message send (kernel-bypass w/Solarflare NIC)	4.0000	5
Serialization delay (1500 byte packet) ? 1Gb Ethernet	12.0000	5
Match marketable equity order	16.0000	5
Send 2K bytes over 1 Gbps network 	20.0000	2,3
Roundtrip ? SDP on Infiniband	20.0000	4
Thread context switch in Linux (worst case)	30.0000	6
Roundtrip ? TCP over Infiniband	50.0000	4
Roundtrip ? TCP over 10Gb Ethernet	50.0000	4
Roundtrip ? TCP over 1Gb Ethernet	100.0000	4
Read 1 MB sequentially from memory 	250.0000	2,3
Minimum Java GC pause time (IBM real-time GC)	250.0000	7
Round trip within same datacenter 	500.0000	3
Disk seek 	10,000.0000	3
Typical "average" Java GC pause time (???)	10,000.0000	???
Read 1 MB sequentially from disk 	20,000.0000	3
Send packet CA->Netherlands->CA	150,000.0000	2,3


Sources:

1."Software Optimization Resources", Agner Fog, http://agner.org/optimize
2."Teach Yourself Programming in Ten Years", Peter Norvig, http://norvig.com/21-days.html
3."Numbers Everybody Should Know", Manuel Simon,http://axisofeval.blogspot.com/2010/11/numbers-everybody-should-know.html
4."Latency Revisited", Cinnober,http://cinnober.com/sites/cinnober.com/files/news/Latency_revisited.pdf
5."Nanosecond Latency Management",  Corvil, http://www.corvil.com
6."How long does it take to make a context switch", Benoit Sigoure,http://blog.tsunanet.net/2010/11/how-long-does-it-take-to-make-context.html
7."Metronome GC", IBM,http://domino.research.ibm.com/comm/research_projects.nsf/pages/metronome.metronomegc.html

I've been keeping a version of these numbers for a while. Here's a list with original sources (as far as I could tell). It would be nice if this were up on a wiki somewhere...