Systems and method for the management and processing of resource requests by a service provider, such as a content delivery network (“CDN”) service provider, on behalf of a content provider are provided. The CDN service provider can measure the performance associated with the delivery of resources to requesting client computing devices from various computing devices associated with the CDN service provider. In one embodiment, the CDN service provider can utilize commands responsive to an initial request for a resource that causes the requesting client computing device to transmit one or more supplemental resource requests. Information associated with the processing of the sequence of resource requests can be used to measure CDN service provider latencies.