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

ptarjan

Scaling your API with rate limiters

The following are examples of the four types rate limiters discussed in the accompanying blog post. In the examples below I've used pseudocode-like Ruby, so if you're unfamiliar with Ruby you should be able to easily translate this approach to other languages. Complete examples in Ruby are also provided later in this gist.

In most cases you'll want all these examples to be classes, but I've used simple functions here to keep the code samples brief.

Request rate limiter

This uses a basic token bucket algorithm and relies on the fact that Redis scripts execute atomically. No other operations can run between fetching the count and writing the new count.

ragingwind

Backend Architectures

Twitter

ror, scala, jetty, erlang, thrift, mongrel, comet server, my-sql, memchached, varnish, kestrel(mq), starling, gizzard, cassandra, hadoop, vertica, munin, nagios, awstats

• Introduce Gizzard of Twitter - 트위터의 새로운 분산 관리 라이브러리 Gizzard를 소개합니다.
• The Architecture Twitter Uses to Deal with 150M Active Users, 300K QPS, a 22 MB/S Firehose, and Send Tweets in Under 5 Seconds
• Scaling Twitter: Making Twitter 10000 Percent Faster

redinger

Setting up Emacs daemon on OS X

Tired of waiting for emacs to start on OS X? This step by step guide will teach you how to install the latest version of emacs and configure it to start in the background (daemon mode) and use emacsclient as your main editor.

Install Cocoa Emacs

Download the latest pretest version of [Emacs for Mac OS X]: http://emacsformacosx.com/builds

mourjo

;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
;; Commentary                                                            ;;
;;                                                                       ;;
;; The goal for writing this started with the idea to have tests run in  ;;
;; parallel using the leiningen plugin eftest                            ;;
;; https://github.com/weavejester/eftest.                                ;;
;;                                                                       ;;
;; With tests using with-redefs, it was not possible to run them in      ;;
;; parallel if they were changing the root binding of the same           ;;
;; vars. Here, we are binding the root of the var to one function that   ;;

stuarthalloway

;; Datomic example code
(use '[datomic.api :only (db q) :as d])

;; ?answer binds a scalar
(q '[:find ?answer :in ?answer]
   42)

;; of course you can bind more than one of anything
(q '[:find ?last ?first :in ?last ?first]
   "Doe" "John")

anthonytxie

 def calc_allocations(self, date, quantity, cap):
        """Figure out ideal allocations for a given date"""
        # {
        #     coin_name: (percent_allocation, data)
        # }

        top_market = self.get_top_market(date, quantity)
        total_cap = sum([coin.market_cap for coin in top_market])

        allocations = [{

cgrand

;; I could have used a closed dispatch (aka cond) but you may find this version more enjoyable
;; the spec format is the one provided by BG

(defprotocol Selector
  (-select [s m]))

(defn select [m selectors-coll]
  (reduce conj {} (map #(-select % m) selectors-coll)))

(extend-protocol Selector

light44

import nltk
import pandas as pd
import re
import pprint
import operator
import csv
import logging
from stop_words import get_stop_words
from collections import defaultdict
from gensim import corpora

kachayev

-module(barber).
-export([run/2, barber/1, clients/1, simulator/2]).

-define(CUT_DUTAION, 20).

run(RoomSize, Duration) ->
    % create barber
    BPid = spawn(?MODULE, barber, [?CUT_DUTAION]),
    % run simulartor with barber PID
    SPid = spawn(?MODULE, simulator, [BPid, RoomSize]),