minidump.net

Writing a .NET Garbage Collector in C# - Part 9: Frozen segments and new allocation strategy

Tue, 17 Mar 2026 00:00:00 +0000

Using NativeAOT to write a .NET GC in C#. In this part, we look at what the GC must do to properly handle frozen segments, and we change the allocation strategy to make it more efficient.

Writing a .NET Garbage Collector in C# - Part 8: Interior pointers

Tue, 03 Mar 2026 00:00:00 +0000

Using NativeAOT to write a .NET GC in C#. This time, we look at what interior pointers are and why they’re so challenging for the GC. We also introduce the concept of brick table.

Too good to be true: an unexpected profiler trap

Fri, 20 Feb 2026 00:00:00 +0000

Sometimes the most convincing performance gains deserve a second look. A reminder that profiling data can be more subtle than it first appears.

Writing a .NET Garbage Collector in C# - Part 7: Marking handles

Tue, 10 Feb 2026 00:00:00 +0000

Using NativeAOT to write a .NET GC in C#. In the seventh part, we scan and update the handles during the mark phase of the garbage collection.

Writing a .NET Garbage Collector in C# - Part 6: Mark and Sweep

Tue, 27 Jan 2026 00:00:00 +0000

Using NativeAOT to write a .NET GC in C#. In the sixth part, we start implementing the mark phase of the garbage collection.

Investigating a deadlock in Visual Studio

Wed, 17 Dec 2025 00:00:00 +0000

A short investigation that showcases one of the most common problem faced when writing a profiler.

Using profiler function hooks in .NET with Silhouette

Tue, 21 Oct 2025 00:00:00 +0000

In this article, we see what are function hooks, and how to use them in .NET with Silhouette. We also learn how to statically link a library with NativeAOT.

Measuring UI responsiveness in Resharper

Thu, 18 Sep 2025 00:00:00 +0000

A walkthrough of how I built a custom profiler to measure UI responsiveness, using .NET and Silhouette.

Writing a .NET Garbage Collector in C# - Part 5

Tue, 11 Mar 2025 00:00:00 +0000

Using NativeAOT to write a .NET GC in C#. In the fifth part, we learn how to decode the GCDesc to find the references of a managed object.

Pro .NET Memory Management 2nd Edition

Tue, 04 Mar 2025 00:00:00 +0000

Pro .NET Memory Management 2nd Edition is available! What should you expect from it? Should you buy it if you already own the 1st edition?

Writing a .NET Garbage Collector in C# - Part 4

Tue, 18 Feb 2025 00:00:00 +0000

Using NativeAOT to write a .NET GC in C#. In the fourth part, we see how walk the heap and how to keep track of allocation contexts.

Writing a .NET Garbage Collector in C# - Part 3

Tue, 11 Feb 2025 00:00:00 +0000

Using NativeAOT to write a .NET GC in C#. The third part adds some tooling to inspect the objects stored on the heap.

Writing a .NET Garbage Collector in C# - Part 2

Tue, 04 Feb 2025 00:00:00 +0000

Using NativeAOT to write a .NET GC in C#. The second part builds the simplest possible GC that can run basic .NET applications.

Writing a .NET Garbage Collector in C# - Part 1

Tue, 28 Jan 2025 00:00:00 +0000

First part of a series of articles about writing a .NET Garbage Collector in C# using NativeAOT. This part sets the expectations and setups the project, dealing with the first difficulties.

Writing a .NET profiler in C# - Part 5

Tue, 07 Jan 2025 00:00:00 +0000

Part 5 of the series about using NativeAOT to write a .NET profiler in C#. We have all the foundations, we’re finally writing an actual profiler.

Using Windows Error Reporting in .NET

Tue, 03 Sep 2024 00:00:00 +0000

A look into how to use Windows Error Reporting to collect crash information for your .NET apps.

Crash in the crash-analyzer

Tue, 09 Apr 2024 00:00:00 +0000

When the tool you write to debug crashes crashes. A story of advanced printf-debugging.

GummyCat - Visualize the activity of the .NET garbage collector

Tue, 27 Feb 2024 00:00:00 +0000

A new tool to visualize the activity of the .NET garbage collector.

Dumping the managed heap in C#

Tue, 13 Feb 2024 00:00:00 +0000

Using unsafe hacks to walk the managed heap from within a .NET application, without relying on the debugging API.

Exploring .NET frozen segments

Sun, 14 Jan 2024 00:00:00 +0000

Exploring a little-known API allowing to allocate managed objects outside of the managed heap.

Memory alignment of doubles in C#

Sat, 30 Sep 2023 00:00:00 +0000

A deep dive into the weird tricks used by the .NET allocator to align arrays of doubles.

SuppressGCTransition

Sat, 12 Aug 2023 00:00:00 +0000

Deep-dive into the SuppressGCTransition attribute introduced in .NET 5.

Writing a .NET profiler in C# — Part 4

Sat, 10 Jun 2023 00:00:00 +0000

Part 4 of the series about using NativeAOT to write a .NET profiler in C#, learning many things about native interop in the process. In this part, we learn how to call methods from ICorProfilerInfo.

VerificationException in .NET Framework when using structs

Mon, 01 May 2023 00:00:00 +0000

A surprising error occuring when using C# 7.3 with partial trust.

Writing a .NET profiler in C# — Part 3

Fri, 03 Mar 2023 00:00:00 +0000

Part 3 of the series about using NativeAOT to write a .NET profiler in C#, learning many things about native interop in the process. In this part, we write a source generator to automatically generate the boilerplate code needed to implement the ICorProfilerCallback interface.

Reading .NET performance counters without the PerfCounter API

Sun, 12 Feb 2023 00:00:00 +0000

A faster and safer way to read .NET performance counters from within.

Writing a .NET profiler in C# — Part 2

Wed, 11 Jan 2023 00:00:00 +0000

Part 2 of the series about using NativeAOT to write a .NET profiler in C#, learning many things about native interop in the process. In this part, we improve the code from the previous article by using instance methods instead of static methods.

Using GC.KeepAlive in async methods

Mon, 05 Sep 2022 00:00:00 +0000

GC.KeepAlive may not work the way you intend when using it in async methods.

Why function pointers can't be used on instance methods in C#

Tue, 26 Jul 2022 00:00:00 +0000

The C# specification indicates that function pointers can only be used on static methods. This article explains why.

Writing a .NET profiler in C# - Part 1

Mon, 11 Jul 2022 00:00:00 +0000

Part 1 of the series about using NativeAOT to write a .NET profiler in C#, learning many things about native interop in the process. In this part, we will see how to mimic a COM interface in C#.

Writing native WinDbg extensions in C#

Tue, 08 Feb 2022 00:00:00 +0000

Using NativeAOT and ClrMD to write a native WinDbg extension in .NET.

Finding an instance of thread by id in WinDbg

Thu, 16 Sep 2021 00:00:00 +0000

How to find an instance of System.Threading.Thread by id in WinDbg, with a .NET Core memory dump.

Reading AsyncLocal values from a memory dump

Thu, 16 Sep 2021 00:00:00 +0000

This article explains how AsyncLocal values are stored in .NET and how to retrieve them from a memory dump.

Analyze your memory dumps in C# with DynaMD

Fri, 16 Jul 2021 00:00:00 +0000

Browse memory structures from a memory dump in C#, just like you would with ClrMD, but in a more fluent way.

Showing unresolved functions in PerfView

Wed, 02 Jun 2021 00:00:00 +0000

How to tell PerfView to stop grouping unresolved functions under the same “?!?” label.

An unconventional way of investigating a NullReferenceException

Tue, 16 Mar 2021 00:00:00 +0000

Digging into a bug in the .NET ARM64 runtime, learning about dispatch stubs, and using that knowledge to diagnose a NullReferenceException.

Debugging a native deadlock in a .NET Linux application

Tue, 09 Feb 2021 00:00:00 +0000

This story begins when one of our integrations tests started got stuck on one PR that seemingly impacted unrelated code. This is a nice excuse to cover some concepts I haven’t touched in my previous articles, such as downloading the .NET symbols on Linux.

AccessViolation in ObjectNative::IsLockHeld (part 2 of 2)

Wed, 25 Nov 2020 00:00:00 +0000

This is the second part of an investigation where I tried to understand why an application was randomly crashing with an AccessViolationException. This part starts when, as I ran out of easy things to try, I decided to map the assembly code of the IsLockHeld method to the original C++ code to understand exactly where it crashed.

AccessViolation in ObjectNative::IsLockHeld (part 1 of 2)

Thu, 05 Nov 2020 00:00:00 +0000

Investigating a crash in a .NET application, caused by an AccessViolationException when inspecting the state of a lock.

Investigating an InvalidProgramException from a memory dump (part 3 of 3)

Thu, 10 Sep 2020 00:00:00 +0000

In this series of article, we’re retracing how I debugged an InvalidProgramException, caused by a bug in the Datadog profiler, from a memory dump sent by a customer. This is the last part of the investigation, about figuring out what is wrong with the IL code.

Investigating an InvalidProgramException from a memory dump (part 2 of 3)

Tue, 01 Sep 2020 00:00:00 +0000

In this series of article, we’re retracing how I debugged an InvalidProgramException, caused by a bug in the Datadog profiler, from a memory dump sent by a customer. In this part, we extract the dynamic IL from the memory dump.

Investigating an InvalidProgramException from a memory dump (part 1 of 3)

Wed, 26 Aug 2020 00:00:00 +0000

In this series of article, we’re retracing how I debugged an InvalidProgramException, caused by a bug in the Datadog profiler, from a memory dump sent by a customer. The first part of the investigation is an introduction to using a memory dump from a .NET application to find the information you seek.

Tricked by WebRequest

Fri, 14 Aug 2020 00:00:00 +0000

Even with years of experience, WebRequest managed to surprise me.

Monitor GC stats with a startup hook

Sun, 21 Jun 2020 00:00:00 +0000

Using startup hooks to automatically fetch GC metrics from any .net core application.

Check what .net core GC keywords are enabled without a debugger

Mon, 18 May 2020 00:00:00 +0000

How to inspect arbitrary values in the memory of a .net process on Linux… And find an unexpected bug in the process.

Performance best practices in C#

Tue, 12 May 2020 00:00:00 +0000

Non-exhaustive list of code patterns to avoid in C#, either because they are risky or perform poorly.

.NET ThreadPool starvation, and how queuing makes it worse

Mon, 27 Apr 2020 00:00:00 +0000

Explaining the ThreadPool starvation issue, and how it can be made worse by the way work-items are queued.

Turning your training bike into a Speed remake

Tue, 14 Apr 2020 00:00:00 +0000

Inspiration for quarantine days: how to connect a Raspberry Pi to a training bike to stream the speed to a computer and pause a video when below 20 km/h

Switching back to the UI thread in WPF/UWP, in modern C#

Fri, 28 Feb 2020 00:00:00 +0000

Leveraging the async machinery to transparently switch to the UI thread when needed.

Another way to use your debugging tools

Fri, 21 Feb 2020 00:00:00 +0000

Using debugging tools to get rid of a nagging popup.

Dumping stack objects with ClrMD

Wed, 18 Dec 2019 00:00:00 +0000

How to implement the WinDbg DumpStackObjects command in ClrMD.

Debugging and fixing the Twitch desktop client

Sat, 11 May 2019 00:00:00 +0000

Showing the mindset and methodology involved in the debugging of an application you know almost nothing about.

Writing ClrMD extensions for WinDbg and LLDB

Thu, 14 Mar 2019 00:00:00 +0000

Guide on how to write debugger extensions that are compatible with both WinDbg and LLDB.

Have some fun with .net core startup hooks

Fri, 01 Feb 2019 00:00:00 +0000

How to abuse .net core startup hooks to make apps behave in crazy ways.

Implementing Java ReferenceQueue and PhantomReference in C#

Wed, 09 Jan 2019 00:00:00 +0000

The Java ReferenceQueue is a mechanism that lets you know when an object has been GC’d. How hard can it be to reimplement it in .NET?

Optimizing the WinDbg DML parser

Thu, 03 Jan 2019 00:00:00 +0000

The impact of using the wrong class for the job. Profiling and fixing a performance issue in WinDbg.