Data centers have become an integral part of the backbone infrastructure for information technology. In particular, they provide a cost-efficient solution for provisioning a wide range of computing resources in diverse environments such as business, scientific, and mobile. Owing to the rapid growth of user-defined and user-generated programs, applications and content, the complexity of deploying and operating data centers continues to increase. Considering the high volume of mixed workloads, the diversity of services offered, and the increasing mobility of users across geographically distributed areas, the performance optimization of data centers has become ever more necessary and challenging, especially in view of criteria such as scalability, reliability, manageability, power efficiency, area density, and operating costs. The goal of this workshop is to promote a community-wide discussion to find and identify suitable strategies to enable effective and scalable data center performance optimizations. We are looking for papers that present new techniques, introduce new methodologies, propose new research directions, or discuss strategies for resolving open performance problems of data centers.