measure timing

[niksu]

Find out how long it takes for a frame to be processed by Pax. That is, once the frame arrives, how long it takes before the frame's dropped or sent on to the next port. This might different depending on whether Mono's AOT compiler is used, and would require warming up if the (standard for .NET) JIT compiler is used. It would also be useful to find out how long it takes for the frame to reach Pax after the frame arrives at the NIC, and how long it takes for the Pax process frame to get to the NIC.

In conversation last week about rudimentary testing ideas, @luigirizzo suggested access a pcap file from disk (rather than receiving/sending packets to a network interface) and measuring Pax's processing time.