Re: [dpdk-users] To enable offloading DEV_TX_OFFLOAD_MULTI_SEGS per port and per queue

[Anupama Laxmi <anupamalaxmi4@gmail.com>]

Hi Shrivastav,

Thanks.I suppose setting only

DEV_TX_OFFLOAD_MULTI_SEGS offload is required for

IP fragmentation to taken into effect?Please confirm.

One more query:
 I am attaching the pcap here which shows BAD UDP payload length( 736)
greater than IP payload length (728).
UDP payload length 736 is less than MTU (1500)  so why I am getting this
error.
Whether this tx offload setting

DEV_TX_OFFLOAD_MULTI_SEGS will really help solve this packet transmission issue.

Only if the packet length > MTU then only I suppose packet would be
fragmented based on tx offload setting

DEV_TX_OFFLOAD_MULTI_SEGS.

Best Regards,
Suchetha

On Mon, Apr 8, 2019 at 12:28 PM Shyam Shrivastav <shrivastav.shyam@gmail.com>
wrote:

>
> The particular offload might be pure per port rather than per queue,
> anyway you are enabling it at port level so no need to enable per queue.
>
> Documentation is available at
> http://doc.dpdk.org/guides/prog_guide/poll_mode_drv.html , some relevant
> excerpt
>
> The dev_info->[rt]x_queue_offload_capa returned from
> rte_eth_dev_info_get() includes all per-queue offloading capabilities.
> The dev_info->[rt]x_offload_capa returned from rte_eth_dev_info_get()
> includes all pure per-port and per-queue offloading capabilities. Supported
> offloads can be either per-port or per-queue.
>
>
>
> On Mon, Apr 8, 2019 at 7:18 AM Anupama Laxmi <anupamalaxmi4@gmail.com>
> wrote:
>
>> I would like to enable per port offloading to set TX offloading for
>> multiple segments using DEV_TX_OFFLOAD_MULTI_SEGS. UDP packets were
>> getting
>> dropped with error Bad UDP length > IP payload length as seen in the
>> wireshark capture. This issue is seen after I upgraded to DPDK 18.08.
>> Hence
>> I would like to set the offload DEV_TX_OFFLOAD_MULTI_SEGS per port to
>> allow
>> segmenation of big packets.
>>
>> I am getting the below error when I try to set the above offload.
>>
>> Ethdev port_id=0 tx_queue_id=0, new added offloads 0x9f3e55 must be within
>> pre-queue offload capabilities 0x0 in rte_eth_tx_queue_setup()
>>
>> Please let me know where I am going wrong and how do I set the offload
>> DEV_TX_OFFLOAD_MULTI_SEGS correctly.
>>
>> static const struct rte_eth_txconf tx_conf = {
>>     .tx_thresh = {
>>         .pthresh = TX_PTHRESH,
>>         .hthresh = TX_HTHRESH,
>>         .wthresh = TX_WTHRESH,
>>     },
>>     .tx_free_thresh = 0,
>>     .tx_rs_thresh = 0,
>> };
>>
>>
>> static struct rte_eth_conf port_conf = {
>>         .rxmode = {
>>                 .mq_mode = ETH_MQ_RX_RSS,
>>                 .max_rx_pkt_len = JUMBO_FRAME_MAX_SIZE,
>>                 .split_hdr_size = 0,
>>                 .offloads = (DEV_RX_OFFLOAD_CHECKSUM |
>>                              DEV_RX_OFFLOAD_CRC_STRIP),
>>         },
>>         .rx_adv_conf = {
>>                 .rss_conf = {
>>                         .rss_key = NULL,
>>                         .rss_hf = ETH_RSS_TCP| ETH_RSS_UDP |
>>                              ETH_RSS_TCP | ETH_RSS_SCTP,
>>                 },
>>         },
>>         .txmode = {
>>                 .mq_mode = ETH_MQ_TX_NONE,
>>         },
>> };
>>
>>
>> struct rte_eth_txconf *tx_conf;
>> struct rte_eth_conf local_port_conf = port_conf;
>> if(dev_info.tx_offload_capa & DEV_TX_OFFLOAD_MULTI_SEGS)
>>         {
>>
>>            local_port_conf.txmode.offloads |= DEV_TX_OFFLOAD_MULTI_SEGS;
>>         }
>> ret = rte_eth_dev_configure(port, nbqueue, nbqueue, &local_port_conf);
>> rte_eth_dev_info_get(port, &dev_info);
>>         tx_conf = &dev_info.default_txconf;
>>         tx_conf->offloads = local_port_conf.txmode.offloads;
>>
>>         ret = rte_eth_tx_queue_setup(port, queue,
>> RTE_TEST_TX_DESC_DEFAULT,
>> master_socket_id, &tx_conf);
>>
>
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