The performance question about Triple-speed ethernet

ARP and ICMP just a begining. If the performance is good enougth. I will do the TCP.

The ARP and ICMP base on "Nios II UDP Offload Example" at alterawiki. The base struct is that getting the 32bit data from the ST-sink interface, decoding the data base the protocol, then sending the data to the next IP using the ST-source interface

The ARP flow is :

TSE->error_check->alignment_remove->packet_select->arp_payload_extractor->arp_checker->alignment_inserter_0

->Multiplexer->TSE

The ICMP flow is :

TSE->error_check->alignment_remove->packet_select->icmp_checker->icmp_payload_inserter->alignment_inserter_1

->Multiplexer->TSE

The symbol "->" is Avalon-ST interface. If the name of IP is same in tow flows, it means thar is the same one.

I use the ModelSim to simulate each IP. The data and timing diagram are right. I find that the clock which each IPs spend are small then 60.

The I do another test. I use UDP IP as ECHO server and the PC sends data. I find the throughput is 800Mbit/s(If I use giga network). The throughput is good.

So I don't understand why one packet spends too long but throughput is good ?