gerryyang

# remove specific file from git cache
git rm --cached filename

# remove all files from git cache
git rm -r --cached .
git add .
git commit -m ".gitignore is now working"

gerryyang

libevent vs libuv

Comparing libevent and libuv. My upfront biased: I want to like libevent. However, I want to objectively compare the two and make an informed decision.

What versions are we comparing?

• libevent 2.0.22 (Stable) [2014-01-05]
• libuv 1.8.0 (Stable) [2015-12-15]

gerryyang

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

gerryyang

#!/bin/bash

# delete none images
docker images | grep none | awk -F' ' '{print $3}' | while read f; do docker rmi -f $f; done

# delete all stoped containers
docker rm -f $(docker ps -aq)
docker rm `docker ps -aq`

# delete all images