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Latency numbers every programmer should know

L1 cache reference ......................... 0.5 ns
Branch mispredict ............................ 5 ns                     on recent CPU
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 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 4X memory

@debasishg
debasishg / gist:8172796
Last active March 23, 2026 03:02
A collection of links for streaming algorithms and data structures

General Background and Overview

  1. Probabilistic Data Structures for Web Analytics and Data Mining : A great overview of the space of probabilistic data structures and how they are used in approximation algorithm implementation.
  2. Models and Issues in Data Stream Systems
  3. Philippe Flajolet’s contribution to streaming algorithms : A presentation by Jérémie Lumbroso that visits some of the hostorical perspectives and how it all began with Flajolet
  4. Approximate Frequency Counts over Data Streams by Gurmeet Singh Manku & Rajeev Motwani : One of the early papers on the subject.
  5. [Methods for Finding Frequent Items in Data Streams](http://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.187.9800&rep=rep1&t
@josegonzalez
josegonzalez / access.lua
Created December 3, 2012 18:26
Simple lua file enabling oauth support for nginx via nginx-lua and access_by_lua.
- certain endpoints are always blocked
if nginx_uri == "/_access_token" or nginx_uri == "/_me" then
ngx.exit(403)
end
-- import requirements
local cjson = require "cjson"
-- setup some app-level vars
local app_id = "APP_ID"
@saturation
saturation / .bashrc_ssh
Created October 7, 2012 13:15 — forked from bluegraybox/.bashrc_ssh
Initialize ssh-agent in .bashrc
# Set up ssh-agent
SSH_ENV="$HOME/.ssh/environment"
function start_agent {
echo "Initializing new SSH agent..."
/usr/bin/ssh-agent | sed 's/^echo/#echo/' > "${SSH_ENV}"
echo succeeded
chmod 600 "${SSH_ENV}"
. "${SSH_ENV}" > /dev/null
/usr/bin/ssh-add;
@jboner
jboner / latency.txt
Last active March 31, 2026 17:03
Latency Numbers Every Programmer Should Know
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
@haschek
haschek / .jshintrc
Created May 4, 2012 16:08
JSHint Configuration, Strict Edition
{
// --------------------------------------------------------------------
// JSHint Configuration, Strict Edition
// --------------------------------------------------------------------
//
// This is a options template for [JSHint][1], using [JSHint example][2]
// and [Ory Band's example][3] as basis and setting config values to
// be most strict:
//
// * set all enforcing options to true
@eligrey
eligrey / object-watch.js
Created April 30, 2010 01:38
object.watch polyfill in ES5
/*
* object.watch polyfill
*
* 2012-04-03
*
* By Eli Grey, http://eligrey.com
* Public Domain.
* NO WARRANTY EXPRESSED OR IMPLIED. USE AT YOUR OWN RISK.
*/