ThreadScope Tour

A guided tour of ThreadScope

In this tutorial, we'll be working through concrete examples on using ThreadScope to debug the performance of parallel programs.

We aim to keep each module in the tutorial self-contained, so you can either follow the progression suggested or jump to just the sections we need.

Note that you will need:

• ThreadScope 0.2.1 or higher
• GHC 7.4 or higher. You could try earlier versions, but more advanced features such as spark events will not available

This tutorial was initially written by Well-Typed in the context of the Parallel GHC Project. Feedback would be most appreciated!

Getting Started

1. Installation: install ThreadScope and run a sample trace
2. Hello world: run ThreadScope on a small test program

Basic skills

3. Initial statistics: collect some simple statistics
4. Profile: examine the profile for a real program
5. Profile 2: examine the profile for an improved program
6. Zoom: zooming and bookmarking

Digging into a program with spark events

7. Spark overview
   • GHC RTS flags: a subset of flags relevant to ThreadScope
   • Spark lifecycle: Lifecycle of a spark
8. Spark rates: study spark creation/conversion
9. Spark rates 2: spark debugging continued

Reference

• Downloads: examples used in this tutorial

Planned

1. Trace: custom events
2. Consolidate: tease out the sequential parts of code