What is interesting in this question is the word "performance". Performance is a term in project management that is often associated with quality. So you need to determine how the product or service will be tested. For simple software projects, this may be a simple test plan. For construction projects, this may include inspections required by law. In manufacturing environments, you will sample product to determine quality. The sample size needs to be chosen to be statistically significant without having an adverse impact on the project financial goals.
As the PM, you will also want to review the project deliverable against the requirements to ensure the full scope of the project was met. In simple terms, this is how you determine the performance of the project. The quality plan documents the approach, expectations, and metrics.
If you have a different idea about what performance means, please clarify and I will attempt to answer.