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

evildmp

This document has now been incorporated into the uWSGI documentation:

http://uwsgi-docs.readthedocs.org/en/latest/tutorials/Django_and_nginx.html

Set up Django, nginx and uwsgi

Steps with explanations to set up a server using:

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,

harith

# Utilities for quickly accessing frequently used directories in bash.

# Usage:
#   $ cd /path/to/project/src/
#   $ mark code     # Will create a new shortcut.
#                   # Becomes interactive if a shortcut already exists
#                   # m is an alias for mark. You can also `m code`
#
#   $ code          # From now on, running this anywhere in the shell
#                   # will put you in /path/to/project/src/code

soravux

# Mostly stolen from deap's symbreg GP example
import operator
import math
import random
import string
import inspect
import ctypes

import numpy
from scipy import optimize

soravux

float Q_rsqrt( float number )
{
	long i;
	float x2, y;
	const float threehalfs = 1.5F;
 
	x2 = number * 0.5F;
	y  = number;
	i  = * ( long * ) &y;                       // evil floating point bit level hacking
	i  = 0x5f3759df - ( i >> 1 );               // what the fuck?

sh1n0b1

#!/usr/bin/python

# Quick and dirty demonstration of CVE-2014-0160 by Jared Stafford (jspenguin@jspenguin.org)
# The author disclaims copyright to this source code.

import sys
import struct
import socket
import time
import select

ntddk

kd> .for(r $t0=0; @$t0<dwo(nt!KiServiceLimit); r $t0=@$t0+1){.printf "%y\n", nt!KiServiceTable+(dwo(nt!KiServiceTable+@$t0*4)>>4)}
fffff801`85aa38c4
fffff801`85b3cc10
nt!NtAcceptConnectPort (fffff801`75f238ac)
nt!NtMapUserPhysicalPagesScatter (fffff801`760afb54)
nt!NtWaitForSingleObject (fffff801`75e52d20)
fffff801`85ba51a0
nt!NtReadFile (fffff801`75eb42f0)
nt!NtDeviceIoControlFile (fffff801`75e56740)
nt!NtWriteFile (fffff801`75e9e770)

Neo23x0

This Gist has been transfered into a Github Repo. You'll find the most recent version here.

YARA Performance Guidelines

When creating your rules for YARA keep in mind the following guidelines in order to get the best performance from them. This guide is based on ideas and recommendations by Victor M. Alvarez and WXS.

• Revision 1.4, October 2020, applies to all YARA versions higher than 3.7

ttsiodras

   #
   # I inherited a large code base, where hundreds of code paths end up
   # calling "common_function_called_in_gazillion_places". 
   #
   # And the need arose for this function to access the HTTP request's
   # headers... 
   #
   # What to do? Refactor all the places leading up to here? In a dynamically
   # typed language, with no compiler to tell us the places to refactor?
   #