Re: [dpdk-dev] Wrong TCP Checkum computed by hardware

["Liu, Jijiang" <jijiang.liu@intel.com>]

> -----Original Message-----
> From: Padam Jeet Singh [mailto:padam.singh@inventum.net]
> Sent: Wednesday, October 28, 2015 4:31 PM
> To: Liu, Jijiang
> Cc: dev@dpdk.org; Matthew Hall
> Subject: Re: [dpdk-dev] Wrong TCP Checkum computed by hardware
> 
> 
> > On 28-Oct-2015, at 1:46 pm, Liu, Jijiang <jijiang.liu@intel.com> wrote:
> >
> >
> >
> >> -----Original Message-----
> >> From: Padam Jeet Singh [mailto:padam.singh@inventum.net]
> >> Sent: Wednesday, October 28, 2015 4:12 PM
> >> To: Liu, Jijiang
> >> Cc: dev@dpdk.org; Matthew Hall
> >> Subject: Re: [dpdk-dev] Wrong TCP Checkum computed by hardware
> >>
> >>
> >>> On 28-Oct-2015, at 1:31 pm, Liu, Jijiang <jijiang.liu@intel.com> wrote:
> >>>
> >>>
> >>>> -----Original Message-----
> >>>> From: dev [mailto:dev-bounces@dpdk.org] On Behalf Of Padam Jeet
> >>>> Singh
> >>>> Sent: Wednesday, October 28, 2015 3:20 PM
> >>>> To: Matthew Hall
> >>>> Cc: dev@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.
> >
> > I don't think the txq_flags is 0 if you just initialized the struct
> rte_eth_txconf like that.
> 
> It’s declared as a global static, so it indeed is 0. I also added some debug
> around the init of the queue:
> 
> for (i = 0; i < tx; ++i) {
> 	    ret = rte_eth_tx_queue_setup(port, i, NB_TXD,
> 		rte_eth_dev_socket_id(port), &tx_conf);
> 	    RTE_LOG(INFO, APP, "Port %u TXQ[%d] txflags = %d\n",
> (unsigned)port,
> 	    	i, tx_conf.txq_flags);
> 	    if (ret < 0)
> 		rte_exit(EXIT_FAILURE, "Could not setup up TX queue %d for
> "
> 				"port%u (%d)", i, (unsigned)port, ret);
> 	}
> 
> And got the following result:
> 
> Oct 28 13:55:34 localhost fpnas[1322]: APP: Port 0 TXQ[0] txflags = 0 Oct 28
> 13:55:34 localhost fpnas[1322]: APP: Port 0 TXQ[1] txflags = 0 Oct 28 13:55:34
> localhost fpnas[1322]: APP: Port 1 TXQ[0] txflags = 0 Oct 28 13:55:34 localhost
> fpnas[1322]: APP: Port 1 TXQ[1] txflags = 0 Oct 28 13:55:35 localhost
> fpnas[1322]: APP: Port 2 TXQ[0] txflags = 0 Oct 28 13:55:35 localhost
> fpnas[1322]: APP: Port 3 TXQ[0] txflags = 0
> 
Yes, you are correct, I just noticed you declare  it is static, If possible, send more codes to me, I can help you with this.
> >
> >> Thanks,
> >> Padam