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

timvisee

Falsehoods programmers believe about time

This is a compiled list of falsehoods programmers tend to believe about working with time.

Don't re-invent a date time library yourself. If you think you understand everything about time, you're probably doing it wrong.

Falsehoods

• There are always 24 hours in a day.
• February is always 28 days long.
• Any 24-hour period will always begin and end in the same day (or week, or month).

djspiewak

Thread Pools

Thread pools on the JVM should usually be divided into the following three categories:

1. CPU-bound
2. Blocking IO
3. Non-blocking IO polling

Each of these categories has a different optimal configuration and usage pattern.

enricofoltran

package main

import (
	"context"
	"flag"
	"fmt"
	"log"
	"net/http"
	"os"
	"os/signal"

SlexAxton

gifify() {
  if [[ -n "$1" ]]; then
    if [[ $2 == '--good' ]]; then
      ffmpeg -i $1 -r 10 -vcodec png out-static-%05d.png
      time convert -verbose +dither -layers Optimize -resize 600x600\> out-static*.png  GIF:- | gifsicle --colors 128 --delay=5 --loop --optimize=3 --multifile - > $1.gif
      rm out-static*.png
    else
      ffmpeg -i $1 -s 600x400 -pix_fmt rgb24 -r 10 -f gif - | gifsicle --optimize=3 --delay=3 > $1.gif
    fi
  else

toddb

/**
* @license Copyright (c) 2012, toddb GoneOpen Limited.
* Available via the MIT or new BSD license.
* based on https://gist.github.com/966776 (mathieul) and forked to https://gist.github.com/1474205

* jasmine.requirejs() returns a function that will load the file(s) required
* and will wait until it's done before proceeding with running specs.
* The function returned is intended to be passed to beforeEach() so the file(s)
* is(are) loaded before running each spec.
*

ErikAugust

#include <stdio.h>
#include <stdlib.h>
#include <stdint.h>
#ifdef _MSC_VER
#include <intrin.h> /* for rdtscp and clflush */
#pragma optimize("gt",on)
#else
#include <x86intrin.h> /* for rdtscp and clflush */
#endif

katef

#!/usr/bin/awk -f

# This program is a copy of guff, a plot device. https://github.com/silentbicycle/guff
# My copy here is written in awk instead of C, has no compelling benefit.
# Public domain. @thingskatedid

# Run as awk -v x=xyz ... or env variables for stuff?
# Assumptions: the data is evenly spaced along the x-axis

# TODO: moving average

zacharycarter

Binding to C Libraries with Nim

---

Table of Contents

• Introduction
• C2Nim
• The C Preprocessor
• Pragmas

danveloper

Ratpack Production Tunings

# cat /etc/security/limits.conf

*         hard    nofile      500000
*         soft    nofile      500000
root      hard    nofile      500000
root      soft    nofile      500000