[dpdk-dev] Intel I350 fails to work with DPDK

[Richardson, Bruce]

> -----Original Message-----
> From: dev [mailto:dev-bounces at dpdk.org] On Behalf Of sabu kurian
> Sent: Wednesday, May 28, 2014 10:42 AM
> To: dev at dpdk.org
> Subject: [dpdk-dev] Intel I350 fails to work with DPDK
> 
> I have asked a similar question before, no one replied though.
> 
> I'm crafting my own packets in mbuf's (74 byte packets all) and sending it
> using
> 
> ret = rte_eth_tx_burst(port_ids[lcore_id], 0, m_pool,burst_size);
> 
> When burst_size is 1, it does work. Work in the sense the NIC will continue
> with sending packets, at a little over
> 50 percent of the link rate. For 1000 Mbps link rate .....The observed
> transmit rate of the NIC is 580 Mbps (using Intel DPDK). But it should be
> possible to achieve at least 900 Mbps transmit rate with Intel DPDK and
> I350 on 1 Gbps link.
> 
> Could someone help me out on this ?
> 
> Thanks and regards

Sending out a single packet at a time is going to have a very high overhead, as each call to tx_burst involves making PCI transactions (MMIO writes to the hardware ring pointer). To reduce this penalty you should look to send out the packets in bursts, thereby saving PCI bandwidth and splitting the cost of each MMIO write over multiple packets.

Regards,
/Bruce