# Suggestions

## Development Suggestions

Your TAs find **some tools very useful** during the development, see [Development Tools](https://pkuflyingpig.gitbook.io/pintos/appendix/development-tools) for details.

<mark style="color:red;">**You should expect to (always) run into bugs that you simply don't understand while working on this and subsequent projects.**</mark>

* When you do, reread the appendix on debugging tools, which is filled with useful debugging tips that should help you to get back up to speed (see section [Debugging](https://pkuflyingpig.gitbook.io/pintos/getting-started/debug-and-test/debugging)).
* Be sure to read the section on backtraces (see section [Backtraces](https://pkuflyingpig.gitbook.io/pintos/getting-started/debug-and-test/debugging#backtraces)), which will help you to get the most out of every kernel panic or assertion failure.

{% hint style="info" %}
**Tips**

We also suggest you **read the** [**Your Tasks**](https://pkuflyingpig.gitbook.io/pintos/project-description/lab1-threads/your-tasks) **as well as the** [**FAQs**](https://pkuflyingpig.gitbook.io/pintos/project-description/lab1-threads/faq) **carefully** -- perhaps multiple times. A lot of the confusion comes from not reading them carefully.
{% endhint %}

{% hint style="info" %}
**Tips**

**`make check` runs all tests.**

If you are debugging one test, you can run just that test with `make tests/threads/<test_case>.result`. Read the [Testing](https://pkuflyingpig.gitbook.io/pintos/getting-started/debug-and-test/testing) part for more details.
{% endhint %}

## Suggested Order of Implementation

We suggest first implementing the following, which can happen in parallel:

* **Optimized `timer_sleep()`** in Exercise 1.1.
* **Basic support for priority scheduling** in Exercise 2.1 when a new thread is created in `thread_create()`.
* **Implement fixed-point real arithmetic routines** ([Fixed-Point Real Arithmetic](https://pkuflyingpig.gitbook.io/pintos/appendix/4.4bsd-scheduler#fixed-point-real-arithmetic)) that are needed for MLFQS in exercise 3.1.
* Then you can add **full support for priority scheduling** in Exercise 2.1 by considering all other possible scenarios and the synchronization primitives.
* Then you can **tackle either Exercise 3.1 first or Exercise 2.2 first**.