swlaschin

Functional Track talks from NDC London 2017

Also, here is the list of all videos from NDC London 2017:

• YouTube
• Vimeo

Wednesday 2017-01-18

benaadams

using System;
using System.Collections.Generic;
using System.Collections;
using System.Diagnostics;
using System.Runtime.CompilerServices;

namespace IListPerformance
{
    public class Program
    {

iamarkdev

/*

Preface:

I'm issuing this challenge as I've hit a major roadblock in the development process
of one of my personal side projects. I've spent the last 2 weeks exhaustively exploring
solutions to the following problem and I'm at my wits end. I've taken a number of approaches
using various tree data structures and clever algorithms with no success. 

mrange

Performance comparison of different data pipelines in .NET

Full source code can be found here

Changelog

1. 2016-12-20
2. New performance test - Paul Westcott (@manofstick) made me aware that SeqComposer has a more performant API. SeqComposer2 uses this API.
3. 2016-12-23

augustoproiete

// Credits: John Stewien
// From: http://code.cheesydesign.com/?p=572

/*
Reading the Portable Executable (PE) header in C#
My job consists of writing fully custom applications for groups of people. The time pressure of these projects is quite high, so generally people start using the application while I’m still writing it, which means I write it modularly and add features as I go along. I also fix bugs as they are discovered. My clients are 2 tiered where expert users get a new build first, they test if for a while, and if they think it’s acceptable they then pass it on to others.

This method of distribution is quite ad-hoc so when a client rings me up and asks me to view their screen to look at something, it’s useful to know what build they are running. To facillitate this I print the link date in the main Window Title so I instantly have an idea about how old the version is that I am looking at. This date is calculated at run time. To do this requires reading in the Portable Executable (PE) header from th

monocasa

/* Compile with
 * gcc -O2 -Wall -Wextra -pedantic -o test_bits test_bits.c
 */

#define _GNU_SOURCE
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <sched.h>
#include <stdint.h>

hernamesbarbara

Principles of Adult Behavior

1. Be patient. No matter what.
2. Don’t badmouth: Assign responsibility, not blame. Say nothing of another you wouldn’t say to him.
3. Never assume the motives of others are, to them, less noble than yours are to you.
4. Expand your sense of the possible.
5. Don’t trouble yourself with matters you truly cannot change.
6. Expect no more of anyone than you can deliver yourself.
7. Tolerate ambiguity.
8. Laugh at yourself frequently.

riverar

<assembly xmlns="urn:schemas-microsoft-com:asm.v1" manifestVersion="1.0" xmlns:asmv3="urn:schemas-microsoft-com:asm.v3" >
  <asmv3:application>
    <asmv3:windowsSettings xmlns="http://schemas.microsoft.com/SMI/2016/WindowsSettings">
      <longPathAware>true</longPathAware>
    </asmv3:windowsSettings>
  </asmv3:application>
</assembly>

pcordes

// x86 SIMD string to uppercase
// See http://stackoverflow.com/questions/735204/convert-a-string-in-c-to-upper-case

#include <stdio.h>
#include <stdint.h>
#include <string.h>
#include <strings.h>  // for ffs
#include <ctype.h>
#include <immintrin.h>

rygorous

Why do compilers even bother with exploiting undefinedness signed overflow? And what are those
mysterious cases where it helps?

A lot of people (myself included) are against transforms that aggressively exploit undefined behavior, but
I think it's useful to know what compiler writers are accomplishing by this.

TL;DR: C doesn't work very well if int!=register width, but (for backwards compat) int is 32-bit on all
major 64-bit targets, and this causes quite hairy problems for code generation and optimization in some
fairly common cases. The signed overflow UB exploitation is an attempt to work around this.