DNSPerf, ResPerf, and DHCPerf are free tools developed by Nominum that
make it simple to gather accurate latency and throughput metrics for
Domain Name Service (DNS) and Dynamic Host Configuration Protocol
(DHCP). These tools are easy-to-use and simulate typical Internet so
network operators can benchmark their naming and addressing
infrastructure and plan for upgrades. The latest version of the DNS
test tools (DNSPerf and ResPerf) can be used with new test files that
include IPv6 queries.

DNSPerf "self-paces" the DNS query load to simulate network
conditions. New features in DNSPerf improve the precision of latency
measurements and allow for per packet per-query latency reporting is
possible. DNSPerf is now multithreaded, multiple DNSPerf clients can
be supported in multicore systems (each client requires two
cores). The output of DNSPerf has also been improved so it is more
concise and useful. Latency data can be used to make detailed graphs
so it is simple for network operators to take advantage of the data.

Homepage:
https://www.dns-oarc.net/tools/dnsperf
