mattwarren

/*
The absence of the C# unsafe keyword and switch does not guarantee code
is type or memory safe. It merely prevents the use of pointer types and
fixed size buffers.

The only thing that can guarantee type and memory safety is
verification and CAS/transparency enforcement.

In particular, the absence of unsafe C# blocks does NOT:

mattwarren

Background Info

• https://www.nuget.org/packages/Microsoft.Diagnostics.Runtime
• https://github.com/Microsoft/clrmd
• http://mattwarren.org/2018/06/15/Tools-for-Exploring-.NET-Internals/#tools-based-on-clr-memory-diagnostics-clrmd
• https://github.com/Microsoft/clrmd/blob/master/Documentation/GettingStarted.md
• https://github.com/dotnet/symstore/tree/master/src/dotnet-symbol

---

mattwarren

Background Info

Download the official Microsoft release or the latest one on GitHub

DON'T BE PUT OFF BY THE UI (But if you are take a look at CodeTrack)

Challenges

• Run a memory profile on one of your own .NET apps (or download and interesting sample one, e.g. NerdDinner or similar)
  • If all else fails, follow this tutorial that includes the code for a simple 'sample app'

mattwarren

Background Info

A .NET library to make Benchmarking easy! See https://benchmarkdotnet.org/ and in-particular the Getting Started Guide the Main Features List

---

Hello World

Add the NuGet package Install-Package BenchmarkDotNet

mattwarren

On the topic of tail calls in .NET

Let's say you have implemented a small data pipeline library to replace LINQ.

module TrivialStream =
  type Receiver<'T> = 'T            -> unit
  type Stream<'T>   = Receiver<'T>  -> unit

  module Details =

mattwarren

using BenchmarkDotNet.Attributes;
using BenchmarkDotNet.Attributes.Columns;
using BenchmarkDotNet.Configs;
using BenchmarkDotNet.Running;
using System;
using System.Collections;
using System.Collections.Generic;
using System.Linq;
using System.Runtime.CompilerServices;

mattwarren

/**
veh_hook Vectored Exception Handler hooking library
Version: 24-March-2008
**/
#define WINVER 0x0501
#define _WIN32_WINNT 0x0501
#include <windows.h>
#include "veh_hook.h"

static veh_list_t* list = NULL;

mattwarren

/*
Q: At which size is it preferrable to use binary search over a simple linear search for a small ordered set?

R: Under 5 elements, linear search is slightly faster (from 200% to 10% faster)
But in practice, not sure a switch case to select the best method is really worth it
Unless main usecase is having most of the time only 1-2 elements (so it could be optimized manually without a loop and switch to binary otherwise)
At 3-4 elements, linear is only 10-5% faster

Relative performance between linear and binary search:
size   x86     x64

mattwarren

    [Config(typeof(Config))]
    public class ContinueWithAllocations
    {
        private class Config : ManualConfig
        {
            public Config()
            {
                Add(new MemoryDiagnoser());
            }
        }

mattwarren

using Microsoft.Diagnostics.Runtime;
using System;
using System.Collections.Generic;
using System.Diagnostics;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace SDDTriage
{