Hi,

I am using iperf v 2.0.5 for testing 10G card. Its a dual port card. Two 16 core machines with 64GB RAM are connected back to back.

In TCP Bidirectional test case sending throughput decrease as compare to TCP Unidirectional test case sending .

All cases use default setting . No extra parameter is set.


In case of 4 Client threads Output comes :--

Unidirectional Send Process --- 9.6 Gbps                

Bidirectional Send Process ----  4.9  Gbps


In case of 8 Client threads Output comes :--

Unidirectional Send Process --- 9.7 Gbps

Bidirectional Send Process -- 6.4 Gbps  


In case of 16 Client threads Output comes :--

 Unidirectional Send Process --- 9.7 Gbps
 
 Bidirectional Send Process --    8 Gbps


 Is this problem regarding TCP/IP stack or nic card ?

Regards

varun