Systems and methods for managing request routing functionality associated with resource requests for one or more resources associated with a content provider are provided. A content delivery network (“CDN”) service provider, on behalf of a content provider, can process domain name service (“DNS”) requests for resources by computing devices and resolve the DNS requests by the identification of a network address of a computing device that will provide the requested resources. Based on the processing of DNS queries initiated by a client computing device, the CDN service provider can measure CDN service provider latencies associated with the generation of DNS requests by network components associated with the client computing devices. Examples of the network components can include DNS resolvers associated with the client computing devices.