The gem5 assignment template repository

This repository is set up so that you can easily use it as a template repository for gem5-based assignments.

This repo contains all of the "general" requirements for gem5-based assignments. For each assignment, you should create a fork of this repository with the template code needed for that particular assignment.

This repository can be used in Codespaces to provide a complete development environment for students to work on the assignments.

Assignments

The assignment text can be found in the assignment.md file in subdirectories of the assignments directory. Each assignment is structured as a single research question for which the students must develop hypotheses, design experiments, and analyze results. Below is the list of assignments in order of increasing difficulty:

• Getting started: A simple assignment to get students started with gem5. This will introduce the students to how to use gem5, codespaces, etc.
• ISA vs Technology: This assignment compares the performance difference of x86, Arm, and RISC-V ISAs on a simple matrix multiplication workload. The performance is compared across ISAs and between 1 GHz and 4 GHz. The goal is to use the Iron Law of Performance to explain the results.
• Pipelining: This assignment compares the performance of an in-order CPU with different pipeline widths, latencies, and depths. The goal is to understand the impact of the pipeline on performance.
• Out of Order CPU: This assignment digs into how different parameters of an out-of-order CPU, including width, ROB size, and the number of physical registers, impact performance. This assignment uses a variety of workloads to showcase the differences in how these parameters impact performance.
• Blocked matrix-multiply: This assignment uses blocked matrix multiply to show the importance of algorithm design on the performance of caches. It reinforces the AMAT calculation and the impact of cache size on performance.
• Virtual memory: (Coming soon) This assignment will explore the impact of virtual memory on performance.
• False sharing: This assignment looks at the impact of false sharing on performance. It uses a simple parallel workload, shows 6 different implementations, and asks the students to figure out why the performance is different.

Using this to create assignments

1. Fork this repository to an assignment-specific repository (e.g., "assignment-1-template") under your classroom organization. This fork can be public or private. I use gem5-assignment<num>-<xq><yy> as the name of the repo.
2. Move the following files to the root of the repository.
   1. The assignment.md file to README.md in the root of the repository. When moving this file, update the due date at the top of the file.
   2. The questions.md file.
   3. The components directory.
3. Delete the assignments directory.
4. Go to github classroom.
   1. Create a new assignment.
   2. Choose the repository you just created as the starter code. (This will create a copy of the repo in your organization.)
   3. Set the repository visibility to private.
   4. Select github codespaces as the editor.
   5. Enable feedback pull requests.
5. Update the page on the class website.
   1. Copy the assignment text to the website repo.
   2. Copy the invitation link to the website repo.
   3. Update the assignment to have links to the invitations.

Using codespaces

• Note: There isn't a good way to enable prebuilt devcontainers, so the first time students open the codespace it will take a few minutes to clone gem5, etc.

Notes

• The resources in workloads will not have the right paths (in the files gem5-config.json and resources.json) unless the script .devcontainer/on_create.sh is run. This script is automatically run when using codespaces or a devcontainer, but will not automatically run if you're using this repository directly on your local machine.