If you are running load tests it is not enough to just look at response time and throughput. As a performance engineer you also have to look at key components that impact performance: CPU, Memory, Network and Disk Utilization should be obvious. Connection Pools (Database, Web Service), Thread Pools and Message Queues have to be part of monitoring as well. On top of that you want to understand how your individual components that you test (frontend server, backend services, database, middleware, …) communicate with each other. You need to identify any communication bottlenecks because of too chatty components (how many calls between tiers) and to heavy weight conversations (bandwidth requirements).
Listen to this podcast and learn which metrics you should look at while running your load test. As performance engineer you should not only report that the app is slow under a certain load but also give recommendations on which components are to blame.