Re: [dpdk-dev] Performance impact with QoS

[satish <nsatishbabu@gmail.com>]

Hi All,
Can someone please provide comments on queries in below mail?

Regards,
Satish Babu

On Mon, Nov 10, 2014 at 4:24 PM, satish <nsatishbabu@gmail.com> wrote:

> Hi,
> I need comments on performance impact with DPDK-QoS.
>
> We are working on developing a application based on DPDK.
> Our application supports IPv4 forwarding with and without QoS.
>
> Without QOS, we are achieving almost full wire rate (bi-directional
> traffic) with 128, 256 and 512 byte packets.
> But when we enabled QoS, performance dropped to half for 128 and 256 byte
> packets.
> For 512 byte packet, we didn't observe any drop even after enabling QoS
> (Achieving full wire rate).
> Traffic used in both the cases is same. ( One stream with Qos match to
> first queue in traffic class 0)
>
> In our application, we are using memory buffer pools to receive the packet
> bursts (Ring buffer is not used).
> Same buffer is used during packet processing and TX (enqueue and dequeue).
> All above handled on the same core.
>
> For normal forwarding(without QoS), we are using rte_eth_tx_burst for TX.
>
> For forwarding with QoS, using rte_sched_port_pkt_write(),
> rte_sched_port_enqueue () and rte_sched_port_dequeue ()
> before rte_eth_tx_burst ().
>
> We understood that performance dip in case of 128 and 256 byte packet is
> bacause
> of processing more number of packets compared to 512 byte packet.
>
> Can some comment on performance dip in my case with QOS enabled?
> [1] can this be because of inefficient use of RTE calls for QoS?
> [2] Is it the poor buffer management?
> [3] any other comments?
>
> To achieve good performance in QoS case, is it must to use worker thread
> (running on different core) with ring buffer?
>
> Please provide your comments.
>
> Thanks in advance.
>
> Regards,
> Satish Babu
>
>


-- 
Regards,
Satish Babu