sudarshansarolkar

Here's a list of mildly interesting things about the C language that I learned mostly by consuming Clang's ASTs. Although surprises are getting sparser, I might continue to update this document over time.

There are many more mildly interesting features of C++, but the language is literally known for being weird, whereas C is usually considered smaller and simpler, so this is (almost) only about C.

1. Combined type and variable/field declaration, inside a struct scope [https://godbolt.org/g/Rh94Go]

struct foo {
   struct bar {
 int x;

Generating Flame Graphs for Apache Spark

Flame graphs are a nifty debugging tool to determine where CPU time is being spent. Using the Java Flight recorder, you can do this for Java processes without adding significant runtime overhead.

When are flame graphs useful?

Shivaram Venkataraman and I have found these flame recordings to be useful for diagnosing coarse-grained performance problems. We started using them at the suggestion of Josh Rosen, who quickly made one for the Spark scheduler when we were talking to him about why the scheduler caps out at a throughput of a few thousand tasks per second. Josh generated a graph similar to the one below, which illustrates that a significant amount of time is spent in serialization (if you click in the top right hand corner and search for "serialize", you can see that 78.6% of the sampled CPU time was spent in serialization). We used this insight to spee

Install java 8

# Remove java 7
sudo yum remove -y java

# Install basic packages
sudo yum install -y git

# Download and install java 8
wget --no-cookies --no-check-certificate --header "Cookie: gpw_e24=http%3A%2F%2Fwww.oracle.com%2F; oraclelicense=accept-securebackup-cookie" "http://download.oracle.com/otn-pub/java/jdk/8u45-b14/jdk-8u45-linux-x64.tar.gz"

General Background and Overview

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.
Models and Issues in Data Stream Systems
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
Approximate Frequency Counts over Data Streams by Gurmeet Singh Manku & Rajeev Motwani : One of the early papers on the subject.
[Methods for Finding Frequent Items in Data Streams](http://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.187.9800&rep

Virtual Hosts on nginx (CSC309)

When hosting our web applications, we often have one public IP address (i.e., an IP address visible to the outside world) using which we want to host multiple web apps. For example, one may wants to host three different web apps respectively for example1.com, example2.com, and example1.com/images on the same machine using a single IP address.

How can we do that? Well, the good news is Internet browsers

	[gpg]
	program = gpg
	[core]
	pager = less -S
	warnAmbiguousRefs = true
	editor = vim
	excludesfile = /Users/kshibata/.gitignore_global
	[branch]
	autosetuprebase = always
	[rerere]

	import java.util.concurrent.atomic.AtomicLong;
	import java.util.concurrent.BlockingQueue;
	import java.util.concurrent.LinkedBlockingQueue;
	import java.util.concurrent.TimeUnit;
	import java.util.concurrent.Executors;
	import java.util.concurrent.ExecutorService;
	import java.io.BufferedReader;
	import java.io.FileReader;
	import java.io.File;
	import java.io.IOException;

	import click

	import torch
	import torch.autograd
	import torch.nn.functional as F
	from torch.autograd import Variable

	import os
	import random
	import math

	id,_version_,BRAND_s,_root_,type_s,COLOR_s,SIZE_s
	12,,,10,,Blue,XL
	11,,,10,,Red,XL
	10,1445176108735528960,Nike,10,parent,,
	22,,,20,,Blue,XL
	21,,,20,,Red,M
	20,1445176108738674688,Nike,20,parent,,
	32,,,30,,Blue,M
	31,,,30,,Red,XL
	30,1445176108740771840,Puma,30,parent,,

	##################### ElasticSearch Configuration Example #####################

	# This file contains an overview of various configuration settings,
	# targeted at operations staff. Application developers should
	# consult the guide at <http://elasticsearch.org/guide>.
	#
	# The installation procedure is covered at
	# <http://elasticsearch.org/guide/en/elasticsearch/reference/current/setup.html>.
	#
	# ElasticSearch comes with reasonable defaults for most settings,