This post collects some useful commands diagnosing memory dumps. This document is written with a sample apps and tools targeting .NET 9. Some tools still name regions as segments.
Use dotnet-dump to collect a memory dump.Install using dotnet tool install dotnet-dump -g
It can do full dump/mini dump, etc.
I have been running an ASP.NET Core application on Raspberry Pi Zero 2W. In an early performance test, I have deployed an application with two endpoints: / and /data. These endpoints return a simple string response as shown below.
app.MapGet("/", () => { return "Hello World"; }); app.MapGet("/data", (HttpContext ctx) => { ctx.Response.StatusCode = 200; var buffer = ctx.Response.BodyWriter.GetSpan(11); "Hello World"u8.CopyTo(buffer); ctx.Response.BodyWriter.Advance(11); });
The application is compiled for .NET 9, without enabling native AOT. I have measured the performance of these APIs using CHttp tool.
CHttp is a simple tool to test performance of HTTP endpoints.
I recently used IAsyncEnumerable in C# the first time. In this post, I will summarize some of my learnings based on .NET 9.
There is an excellent introduction to Iterating with Async Enumerables that introduces they key concepts from the iterators point of view and then details the internals of an async enumerator.
IAsyncEnumerable<T> allows creating iterators that produce elements in an asynchronous fashion. Although it has been around for a few years, it is not commonly seen in application source code. Typically, iteration happens over a collection where elements are already computed, making synchronous iteration adequate, like iterating a list of integers. There are also cases where the elements of an iterator can computed synchronously, for example the runtime provides Enumerble.Range or Enumerable.Repeat iterators. Additionally, Select extension can project each element of a sequence into a new shape, like a Task<T>, then a consumer awaits these tasks to complete concurrently.
HTTP2 headers can contain string literals that are Huffman encoded for compression. Before processing these headers, servers must first decode them according to RFC 7541.
A string literal in a header consists of three components:
A single bit flag indicating Huffman encoding
The length of the encoded data
The encoded data itself
This post summarizes my learnings about code coverage visualization in SonarQube and GitLab.
I'll detail different options for displaying code coverage for a C# (.NET) application in both tools. GitLab uses Cobertura coverage files. When such a file is uploaded as a job artifact, GitLab marks each line as covered or uncovered in a pull request (Merge Request in GitLab terms). GitLab also provides other coverage features that are not covered in this post.
SonarQube accepts several coverage formats. As of writing this post, for .NET applications it works with coverage files in these formats:
