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hellerbarde / latency.markdown

Created May 31, 2012 13:16 — forked from jboner/latency.txt

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

dergachev / squid-deb-proxy_on_docker.md

Last active May 25, 2023 03:55

Caching debian package installation with docker

TLDR: I now add the following snippet to all my Dockerfiles:

# If host is running squid-deb-proxy on port 8000, populate /etc/apt/apt.conf.d/30proxy
# By default, squid-deb-proxy 403s unknown sources, so apt shouldn't proxy ppa.launchpad.net
RUN route -n | awk '/^0.0.0.0/ {print $2}' > /tmp/host_ip.txt
RUN echo "HEAD /" | nc `cat /tmp/host_ip.txt` 8000 | grep squid-deb-proxy \
  && (echo "Acquire::http::Proxy \"http://$(cat /tmp/host_ip.txt):8000\";" > /etc/apt/apt.conf.d/30proxy) \
  && (echo "Acquire::http::Proxy::ppa.launchpad.net DIRECT;" >> /etc/apt/apt.conf.d/30proxy) \
  || echo "No squid-deb-proxy detected on docker host"

imranity / groovy-create-user.md

Last active April 10, 2024 17:29

Jenkins Groovy enable security and create a user in groovy script

This is a snippet that will create a new user in jenkins and if security has been disabled , it will enable it :)

import jenkins.model.*
import hudson.security.*

def instance = Jenkins.getInstance()

def hudsonRealm = new HudsonPrivateSecurityRealm(false)
hudsonRealm.createAccount("MyUSERNAME","MyPASSWORD")
instance.setSecurityRealm(hudsonRealm)

Timo Mihaljov noidi

Latency numbers every programmer should know