kconner

macOS Internals

Understand your Mac and iPhone more deeply by tracing the evolution of Mac OS X from prelease to Swift. John Siracusa delivers the details.

Starting Points

How to use this gist

You've got two main options:

petrushev

roomrate
========
{
    'city': 'Berlin',
    'hotel': 'Hilton',
    'date': '2013-08-09'
    'room_type': 'single',
    'occupancy': 2,
    'avail_count': 13,
    'booked_count': 4,

artyom

# put this to your $HOME/.bashrc
# so you can safely use screen or tmux while preserving ssh-agent forwarding features
# of your ssh sessions
test "${SSH_AUTH_SOCK:-}" && test $SSH_AUTH_SOCK != $HOME/.ssh_auth_sock && {
        test -L $HOME/.ssh_auth_sock && \
                test "$(readlink $HOME/.ssh_auth_sock)" = $SSH_AUTH_SOCK || \
                ln -sf $SSH_AUTH_SOCK $HOME/.ssh_auth_sock
        export SSH_AUTH_SOCK=$HOME/.ssh_auth_sock
}

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