hellerbarde

Latency numbers every programmer should know

L1 cache reference ......................... 0.5 ns
Branch mispredict ............................ 5 ns
L2 cache reference ........................... 7 ns
Mutex lock/unlock ........................... 25 ns
Main memory reference ...................... 100 ns             
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

kuntalchandra

# Shoot off 300 requests at the server, with a concurrency level of 10, to test the number of requests it can handle per second

# -p POST
# -H Authentication headers
# -T Content-Type
# -c Concurrent clients
# -n Number of requests to run
# -l Accept variable document length
# -k Connection keep-alive
# -v Verbosity level