aras-p

// Just before switching jobs:
// Add one of these.
// Preferably into the same commit where you do a large merge.
//
// This started as a tweet with a joke of "C++ pro-tip: #define private public",
// and then it quickly escalated into more and more evil suggestions.
// I've tried to capture interesting suggestions here.
//
// Contributors: @r2d2rigo, @joeldevahl, @msinilo, @_Humus_,
// @YuriyODonnell, @rygorous, @cmuratori, @mike_acton, @grumpygiant,

pbailis

RapGenius has an interesting post about Heroku's randomized load balancing, complaining about how random placement degrades performance compared to prior omniscient approaches. RapGenius ran some simulations, including an experiments with a "Choice of Two" method:

Choice of two routing is the naive method from before, with the twist that when you assign a request to a random dyno, if that dyno is already busy then you reassign the request to a second random dyno, with no regard for whether the second dyno is busy

This differs subtly but substantially from the standard "Power of Two Choices" randomized load balancing:

each [request] is placed in the least loaded of d >= 2 [Dynos] chosen independently and uniformly at random

Take a look at the difference in queue lengths below, for 200 Dynos, 100

jordansissel

logstash queries graphed with graphite.

Operation: Decouple whisper from graphite.

Method: Create a graphite function that does a date histogram facet query against elasticsearch for a given query string for the time period viewed in the current graph.

Reason: graphite has some awesome math functions. Wouldn't it be cool if we could use those on logstash results?

The screenshot below is using logstash to watch the twitter stream of keywords "iphone" "apple" and "samsung" - then I graph them each, so we get an idea of popularity. As a bonus, I also do a movingAverage() on the iphone curve to show you why this is awesome.

jboner

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

msackman

//  The contents of this file are subject to the Mozilla Public License
//  Version 1.1 (the "License"); you may not use this file except in
//  compliance with the License. You may obtain a copy of the License
//  at http://www.mozilla.org/MPL/
//
//  Software distributed under the License is distributed on an "AS IS"
//  basis, WITHOUT WARRANTY OF ANY KIND, either express or implied. See
//  the License for the specific language governing rights and
//  limitations under the License.
//

lucasfais

Sublime Text 2 – Useful Shortcuts (Mac OS X)

General

⌘T	go to file
⌘⌃P	go to project
⌘R	go to methods
⌃G	go to line
⌘KB	toggle side bar
⌘⇧P	command prompt

dahlia

# 30 minutes Lisp in Ruby
# Hong Minhee <http://dahlia.kr/>
#
# This Lisp implementation does not provide a s-expression reader.
# Instead, it uses Ruby syntax like following code:
#
#     [:def, :factorial,
#       [:lambda, [:n],
#         [:if, [:"=", :n, 1],
#               1,