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

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

Raynos

DOM Libraries, the easy way

• [by. Select elements][1]
• [fragment. Turn HTML into DOMFragments][2]
• [class-list. Cross browser HTML5 classList implementation][3]
• [dom-walk. Traverse the DOM in tree order][4]
• [xhr. Minimal cross browser, cross domain XHR][5]
• [insert. Cross browser DOM4 insertion methods][6]
• [to-array. Convert nodelists into arrays][7]
• [hidden. Cross browser HTML5 hidden property][8]

ashrithr

Introduction to Kafka

Kafka acts as a kind of write-ahead log (WAL) that records messages to a persistent store (disk) and allows subscribers to read and apply these changes to their own stores in a system appropriate time-frame.

Terminology:

• Producers send messages to brokers
• Consumers read messages from brokers
• Messages are sent to a topic

pchiusano

// WARNING! totally untested, I have only compiled the code! :)

package json

import collection.immutable.Map
import scalaz.{\/, MonadPlus}
import scalaz.\/._
import scalaz.std.vector._
import scalaz.std.map._
import scalaz.std.list._

rodneyrehm

some tools for diagrams in software documentation

Diagrams For Documentation

Obvious Choices

• Graphviz
• Pandoc

ASCII

CMCDragonkai

Rust/Haskell: Higher-Kinded Types (HKT)

A higher kinded type is a concept that reifies a type constructor as an actual type.

A type constructor can be thought of in these analogies:

• like a function in the type universe
• as a type with a "hole" in it

popravich

The standard names for indexes in PostgreSQL are:

{tablename}_{columnname(s)}_{suffix}

where the suffix is one of the following:

• pkey for a Primary Key constraint;
• key for a Unique constraint;
• excl for an Exclusion constraint;
• idx for any other kind of index;

robatron

Automatically Prepend a Jira Issue ID to Git Commit Messages

Use a git hook to match a Jira issue ID from the current branch, and prepend it to every commit message

Assuming the current branch contains a Jira issue ID, you can use a git hook script to prepend it to every commit message.

1. Create an empty commit-msg git hook file, and make it executable. From your project's root directory:

    install -b -m 755 /dev/null .git/hooks/commit-msg
   

2. Save the following script to the newly-created .git/hooks/commit-msg file:

vasanthk

System Design Cheatsheet

Picking the right architecture = Picking the right battles + Managing trade-offs

Basic Steps

1. Clarify and agree on the scope of the system

• User cases (description of sequences of events that, taken together, lead to a system doing something useful)
  • Who is going to use it?
  • How are they going to use it?