seboudry

Latency numbers every programmer should know

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

trongthanh

# source: http://st-on-it.blogspot.com/2010/01/how-to-move-folders-between-git.html
# First of all you need to have a clean clone of the source repository so we didn't screw the things up.

git clone git://server.com/my-repo1.git

# After that you need to do some preparations on the source repository, nuking all the entries except the folder you need to move. Use the following command

git filter-branch --subdirectory-filter your_dir -- -- all

# This will nuke all the other entries and their history, creating a clean git repository that contains only data and history from the directory you need. If you need to move several folders, you have to collect them in a single directory using the git mv command.