Hi all,
I found that the destination MAC address is the MAC address of an
active NIC (managed by Linux OS), I can get roughly line rate (1Gbps). If the
destination NIC is bind to the DPDK driver, I can only get 100Mbps. All NICs
are Gigabit-NIC. I use D-Link DGS-1024D Gigabit switch for the NIC connection.
It is not the PAUSE frame. Because, I already disable the flow control
on NICs. Is there any other mechanism that limits the packet sending speed? I
googled for long time, but didn?t find any possible reason.
Does anyone have any suggestion? Thanks.
Best regards,
-xiaozhe
> On Sep 20, 2016, at 11:09 AM, xiaozhe shao <sxz1069 at gmail.com> wrote:
>
> Hi all,
>
> I?m sending packet by rte_eth_tx_burst() function. With 1Gbps NIC, I
> just get 100Mbps speed.
> I use the following code to send packets (In order to send packets, I
> keep calling rte_eth_tx_burst).
>
> for (i=0; i < BURST_SIZE;){
> i = i + rte_eth_tx_burst(port, queue, buffer + i, BURST_SIZE - i);
> }
>
> My NICs are ?Intel Corporation 82572EI Gigabit Ethernet Controller
> (Copper) (rev 06)? and ?Intel Corporation 82576 Gigabit Ethernet Connection
> (rev 01)?. When I get the link state through DPDK, the link_speed is 1000.
>
> I try testpmd with the instructions of ?http://dpdk.org/doc/quick-start
> <http://dpdk.org/doc/quick-start>?. It works well. No dropped packets.
>
> When I send packets with 60 bits length, the rate is only about 140000
> pps. When I send packets with 1500 bits length, the rate is about 8000 pps. I
> only get 100Mbps sending speed.
>
> My OS is ?Linux 3.2.0-4-amd64 #1 SMP Debian 3.2.81-1 x86_64 GNU/Linux?.
> I tried DPDK-2.2.0 and DPDK-16.07. The results are same.
>
> I also found a strange thing. If I send the packet that has the
> destination MAC same with the MAC address of the NIC that sends the packet, I
> can get 1.4Mpps with the 60-bit-length packets.
>
> I profile the sending program with gperf. The ?rte_delay_us? consumes
> more than 90% running time. But I don?t know the caller of ?rte_delay_us?. In
> the output of gperf, ?rte_delay_us? is ?spontaneous?.
>
> I don?t know why I cannot get 1Gbps send speed. Did anyone meet the
> similar issue? How to address it?
>
> Best regards,
> -xiaozhe
