[dpdk-dev] Wrong TCP Checkum computed by hardware
Padam Jeet Singh
padam.singh at inventum.net
Wed Oct 28 09:12:08 CET 2015
> On 28-Oct-2015, at 1:31 pm, Liu, Jijiang <jijiang.liu at intel.com> wrote:
>
>
>> -----Original Message-----
>> From: dev [mailto:dev-bounces at dpdk.org] On Behalf Of Padam Jeet Singh
>> Sent: Wednesday, October 28, 2015 3:20 PM
>> To: Matthew Hall
>> Cc: dev at dpdk.org
>> Subject: Re: [dpdk-dev] Wrong TCP Checkum computed by hardware
>>
>
> Did you set the txq_flags?
> If the flag is not set, the default value is IXGBE_SIMPLE_FLAGS, and the any TX offloads do not work.
>
> See the following codes in ixgbe_rxtx.c file
>
> /* Use a simple Tx queue (no offloads, no multi segs) if possible */
> if (((txq->txq_flags & IXGBE_SIMPLE_FLAGS) == IXGBE_SIMPLE_FLAGS)
> && (txq->tx_rs_thresh >= RTE_PMD_IXGBE_TX_MAX_BURST)) {
> PMD_INIT_LOG(INFO, "Using simple tx code path");
> ...
> dev->tx_pkt_burst = ixgbe_xmit_pkts_simple;
> } else {
> ...
> dev->tx_pkt_burst = ixgbe_xmit_pkts;
> }
>
>
> --Jijiang Liu
I initialise the queue with the following structure:
static const struct rte_eth_txconf tx_conf = {
.tx_thresh = {
.pthresh = 32, /* Ring prefetch threshold */
.hthresh = 0, /* Ring host threshold */
.wthresh = 0, /* Ring writeback threshold */
},
.tx_free_thresh = 0, /* Use PMD default values */
.tx_rs_thresh = 0, /* Use PMD default values */
};
This would set the txq_flags to zero - so the tx_pkt_burst function would always point to ixgbe_xmit_pkts. Also, as observed only TCP checksum is computed wrong when there is VLAN TX Offload + IP Offload + TCP offload bits set. VLAN TX Offload + IP Offload + TCP CKSUM in software generates correct packet on the wire.
Thanks,
Padam
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