p99 0.1.0

p99.NET

Low-cost generation of performance percentiles (p50, p90, p99, p99.9, etc.) for cross-platform .NET workloads.

Table of Contents

• Introduction
• Installation
• Quick start
• Platform support
• Design notes
• Repository layout
• Building from source
  • Pack locally
• Benchmarks
• Packaging and distribution
• Project information
  • Where to get help
  • Contribution guidelines
  • Related projects
  • License

Introduction

p99 is a lightweight, low-overhead library designed for generating real-time performance percentiles in high-frequency or latency-sensitive environments.

p99.NET is the .NET implementation. Companion implementations are available as p99 (C) and p99.Rust (Rust).

Installation

dotnet add package p99

Quick start

using P99;

Histogram histogram = default;

histogram.PushEventTimeNs(120);
histogram.PushEventTimeNs(450);
histogram.PushEventTimeNs(980);

Console.WriteLine($"p50: {histogram.ValueAtP50()} ns");
Console.WriteLine($"p99: {histogram.ValueAtP99()} ns");

See samples/P99.QuickStart for a runnable example.

Platform support

The library multi-targets:

NuGet selects the best-matching assembly for each consumer automatically.

Design notes

Histogram is declared unsafe in C# only to embed its 64 bucket counts in a single contiguous block (fixed ulong _buckets[64]). That matches the C and Rust layouts: no heap allocation for buckets, predictable size, and cache-friendly access. It is not used due to any use of raw pointers, unchecked memory, or any behaviour that callers need to treat as dangerous — the public API is fully safe.

The project sets AllowUnsafeBlocks solely for this layout; consumers do not need to enable unsafe code in their own projects.

Repository layout

p99.NET/
├── src/P99/              # Main library (NuGet package: p99)
├── tests/P99.Tests/      # Unit tests (xUnit)
├── benchmarks/           # Performance benchmarks (BenchmarkDotNet)
├── samples/              # Consumer examples
├── .github/workflows/    # CI and release automation
├── Directory.Build.props   # Shared build and Source Link settings
├── Directory.Packages.props
├── global.json             # Pinned SDK version
├── build.sh / build.ps1    # Local build, test, and pack scripts
└── p99.NET.sln

Building from source

Requires the .NET SDK version specified in global.json.

git clone https://github.com/synesissoftware/p99.NET.git
cd p99.NET
dotnet restore
dotnet build
dotnet test

Pack locally

dotnet pack src/P99/P99.csproj --configuration Release --output artifacts/packages

Or:

./build.sh

Benchmarks

Performance benchmarks use BenchmarkDotNet, mirroring the p99.Rust criterion suite:

dotnet run --project benchmarks/P99.Benchmarks --configuration Release -- --filter '*'

Run a subset:

dotnet run --project benchmarks/P99.Benchmarks -c Release -- --filter '*PushEventTimeNs*'

Use --job short for a quicker local run:

dotnet run --project benchmarks/P99.Benchmarks -c Release -- --job short --filter '*'

Packaging and distribution

This project is designed for adoption as a NuGet package:

• SDK-style project with dotnet pack output;
• Package metadata (PackageId, license expression, readme, tags);
• Symbol packages (.snupkg) for debugging;
• Source Link for stepping into source from consuming projects;
• CI builds on Windows, Linux, and macOS;
• Release workflow publishes to NuGet.org on GitHub Release;

Project information

Where to get help

• GitHub repository;
• Issue tracker;
• NuGet package;

Contribution guidelines

See CONTRIBUTING.md. Defect reports, feature requests, and pull requests are welcome.

Related projects

• p99 — C implementation;
• p99.Python — Python implementation;
• p99.Rust — Rust implementation;

License

This project is licensed under the 3-clause BSD license. See LICENSE.