rsntp is an experimental high-performance NTP server written in Rust. It does not implement a full NTP client and relies on another NTP client and server to be running on the system instead. It periodically updates its state to mirror the real NTP client/server and uses multiple threads to serve the current system time.
By default, rsntp uses one thread for IPv4 and another for IPv6. In order to get the best performance, it’s necessary to increase the number of threads using the --ipv4-threads and --ipv6-threads options to correspond to the number of CPU cores available on the system.
The real NTP client/server needs to be configured to listen on 127.0.0.1 on port 11123 (or another port if specified with the --server-addr option). For instance, the following configuration should work with chronyd:
allow 127.0.0.1 port 11123 bindaddress 127.0.0.1
The following table shows the maximum number of NTP requests handled per second measured on a Linux machine with an Intel E5-1620 CPU (4 cores, 8 threads) and Intel i350 network card.
1 thread |
330 kpps |
2 threads |
530 kpps |
3 threads |
730 kpps |
4 threads |
730 kpps |