Greg Brandt brandtg

About `PrintCompilation`

This note tries to document the output of PrintCompilation flag in HotSpot VM. It was originally intended to be a reply to a blog post on PrintCompilation from Stephen Colebourne. It's kind of grown too big to fit as a reply, so I'm putting it here.

Written by: Kris Mok rednaxelafx@gmail.com

Most of the contents in this note are based on my reading of HotSpot source code from OpenJDK and experimenting with the VM flags; otheres come from HotSpot mailing lists and other reading materials listed in the "References" section.

This

tmux shortcuts & cheatsheet

start new:

tmux

start new with session name:

tmux new -s myname

Introduction

C-a == Ctrl-a
M-a == Alt-a

General

:q        close
:w        write/saves
:wa[!]    write/save all windows [force]
:wq       write/save and close

OS X Screencast to animated GIF

This gist shows how to create a GIF screencast using only free OS X tools: QuickTime, ffmpeg, and gifsicle.

Instructions

To capture the video (filesize: 19MB), using the free "QuickTime Player" application:

This tweaks the darcula IntelliJ theme to better match the solarized color scheme found here https://github.com/jkaving/intellij-colors-solarized

To enable, after installing the color scheme linked above set your theme to darcula.

Preferences -> Appearance -> Theme -> Darcula

Exit IntelliJ then add the tweaked darcula properties file to the idea.jar file with the following command

jar -ufv idea.jar com/intellij/ide/ui/laf/darcula/darcula.properties

PSQL Cheatsheet

Magic words:

psql -U postgres

Some interesting flags (to see all, use -h or --help depending on your psql version):

-E: will describe the underlaying queries of the \ commands (cool for learning!)
-l: psql will list all databases and then exit (useful if the user you connect with doesn't has a default database, like at AWS RDS)

the horror!

The jist of starting and stoping apache:

$ sudo apachectl start
$ sudo apachectl stop
$ sudo apachectl restart

if you care about the HTTPD version

	Latency Comparison Numbers (~2012)
	----------------------------------
	L1 cache reference 0.5 ns
	Branch mispredict 5 ns
	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 us
	Send 1K bytes over 1 Gbps network 10,000 ns 10 us
	Read 4K randomly from SSD* 150,000 ns 150 us ~1GB/sec SSD

	var PUNCTUATION = "" +
	"’'" + // apostrophe
	"()[]{}<>" + // brackets
	":" + // colon
	"," + // comma
	"‒–—―" + // dashes
	"…" + // ellipsis
	"!" + // exclamation mark
	"." + // full stop/period
	"«»" + // guillemets

	Solarized
	#FDF6E3,#EEE8D5,#93A1A1,#FDF6E3,#EEE8D5,#657B83,#2AA198,#DC322F

	Solarized Dark
	#073642,#002B36,#B58900,#FDF6E3,#CB4B16,#FDF6E3,#2AA198,#DC322F