prepor

From http://www.scribd.com/doc/23548865/Debugging-Ruby

lsof
list open files
lsof -nPp <pid>

-n
Inhibits the conversion of network numbers to host names for 
network files.
-P

rajiv-singaseni

package com.webile.upload;

import java.io.BufferedReader;
import java.io.ByteArrayOutputStream;
import java.io.InputStreamReader;
import java.util.Date;

import org.apache.http.HttpResponse;
import org.apache.http.client.HttpClient;
import org.apache.http.client.methods.HttpPost;

ajsutton

import com.lmax.disruptor.RingBuffer;
import com.lmax.disruptor.dsl.Disruptor;

import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;

public class BackgroundLogger
{
    private static final int ENTRIES = 64;

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

waleking

package topic

import spark.broadcast._
import spark.SparkContext
import spark.SparkContext._
import spark.RDD
import spark.storage.StorageLevel
import scala.util.Random
import scala.math.{ sqrt, log, pow, abs, exp, min, max }
import scala.collection.mutable.HashMap

visenger

#!/bin/sh

# one way (older scala version will be installed)
# sudo apt-get install scala

#2nd way
sudo apt-get remove scala-library scala
wget http://www.scala-lang.org/files/archive/scala-2.11.4.deb
sudo dpkg -i scala-2.11.4.deb
sudo apt-get update

mrflip

Tuning Storm+Trident

Tuning a dataflow system is easy:

The First Rule of Dataflow Tuning:
* Ensure each stage is always ready to accept records, and
* Deliver each processed record promptly to its destination

leommoore

#Kafka - Messaging Basics This assumes you are starting fresh and have no existing Kafka or ZooKeeper data. See http://kafka.apache.org/documentation.html#quickstart for more details.

##Install Java

sudo apt-get install python-software-properties
sudo add-apt-repository ppa:webupd8team/java
sudo apt-get update
sudo apt-get install oracle-java8-installer

jdeng

  // generate [0..n-1]
  auto seq = [](size_t n) -> std::vector<size_t> {
      std::vector<size_t> v(n);
      for (size_t i=0; i<n; ++i) v[i] = i;
      return v;
  };
  auto index = seq(n);

  // n * n distance matrix
  std::vector<D> dists(n * n);

g-alonso

= Some yum usage for people who know "apt" =

If you are familiar with the apt package manager on Debian/Ubuntu this page should help you transfer your knowledge to working with yum on Fedora/RHEL/CentOS/etc.

Note that this page as currently written is by non-apt experts, so there may be some mistakes.

== General points ==

 * Speed: 
    * data/CPU: apt on Debian deals with roughly ~37,000 packages[1] and an extra 6,500 "provides"[2]. yum on Fedora deals with roughly 24,000 packages, 143,000 provides and 3,100,000 file provides.