# Deadline Monotonic Scheduling DM

## Schedulability tests for DM

In some cases tasks may have large periods (low frequency) but require a short response time.

In these cases we assign a deadline shorter than the period, and the scheduling criteria is the deadline.

It is possible to use utilization-based tests.

* The adaptation is simple, but the test is **very pessimistic**.

### Utilization-based test

<figure><img src="https://3011170443-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2FxBNeQZTqLnbb3C3JTlRu%2Fuploads%2F0XzBu1XWYhCwoY4TC1rS%2Fa.png?alt=media&#x26;token=1fbd706b-3643-4411-b0d5-ccb286690ef8" alt=""><figcaption></figcaption></figure>

E.g. *{C = 0.5, T = 2, D = 1}* (Assumed utilization is doubled).

<figure><img src="https://3011170443-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2FxBNeQZTqLnbb3C3JTlRu%2Fuploads%2FqY1edJMVXG8jJTgAD7Sg%2Fa.png?alt=media&#x26;token=47d7502d-c3ea-4532-8d2e-bcfc45b4914d" alt=""><figcaption></figcaption></figure>
