1. A computer system, comprising: a client device, comprising: a network interface; a memory; and one or more processors communicatively coupled to the memory, wherein the memory comprises program instructions executable by the one or more processors to implement a performance monitoring component configured to: for multiple individual host systems: receive metric information in a decentralized manner, wherein the metric information is received at the network interface of the client device from a respective network-based interface of that host system; wherein for one or more metrics, the metric information indicates multiple values of that metric at different instances in time; wherein the one or more metrics are associated with performance of that host system; and generate a user interface display comprising a graphical representation of the metric information from the plurality of host systems; wherein receipt of the metric information from the multiple host systems is an initial aggregation of the metric information from the multiple host systems together on the client device, wherein the initial aggregation foregoes the use of a centralized data store to aggregate the metric information from the multiple host systems prior to transmittal to the client device.