Network slicing has been taking a major role in upcoming 5G network implementations. However, in order to provision and maintain end-to-end slices, the management and orchestration among different network segments is required. As a result, techniques and components have risen to fulfil these tasks. In this work, we present latency-aware slicing, which is enabled by the provisioning of network slices equipped with an end-to-end latency sensor. This sensor is added to the service chain, allowing for real time monitoring and eventually actuation upon latency requirements violations. Moreover, we introduce an architecture capable of handling the deployment of such sensors while also coordinating the provisioning of the slice across optically interconnected DCs. To experimentally demonstrate the deployment of a slice with latency sensing we set up a multi-segment testbed connecting client VMs. The presented results demonstrate the behavior of the latency sensor and how it enables latency optimization through path reconfiguration.