[dpdk-dev] [PATCH v3] net/tap: remove queue specific offload support

[Ophir Munk]

> -----Original Message-----
> From: Ferruh Yigit [mailto:ferruh.yigit at intel.com]
> Sent: Wednesday, April 25, 2018 12:48 PM
> To: Ophir Munk <ophirmu at mellanox.com>; Pascal Mazon
> <pascal.mazon at 6wind.com>
> Cc: dev at dpdk.org; Mordechay Haimovsky <motih at mellanox.com>; Olga
> Shern <olgas at mellanox.com>; Thomas Monjalon <thomas at monjalon.net>;
> Raslan Darawsheh <rasland at mellanox.com>; Shahaf Shuler
> <shahafs at mellanox.com>
> Subject: Re: [PATCH v3] net/tap: remove queue specific offload support
> 
> On 4/25/2018 10:18 AM, Ophir Munk wrote:
> > Hi Ferruh,
> >
> > I should have mentioned earlier that TAP does support queue specific
> capabilities.
> > Please look in tap_queue_setup() and note that each TAP queue is created
> with a distinct file descriptor (fd).
> > Then supporting an offload capability is just implementing it in SW (e.g.
> calculating IP checksum).
> >
> > If the main assumption of this patch was that TAP does not support queue
> specific offloads - then please consider this patch again.
> 
> Yes that was the initial question, is tap supports queue specific offloads or
> not. Thanks for the answer.
> 
> >
> > On the other hand there is no port specific capability supported by TAP.
> 
> If so verify functions are wrong, that was the error I got.

Can you please specify the test you did what error you got? 
If I fix something I want to verify what I am fixing.

> It seems copy/paste of mlx one but the port_supp_offloads has different
> meaning there.
> 
> > However, in order to support legacy applications, port capabilities are
> usually reported as the OR operation between queue & port capabilities.
> > TAP currently clones the queue capabilities to port capabilities. We could
> optimize this cloning by always return queue capabilities when queried about
> queues or ports. In this case - tap_rx_offload_get_port_capa() and
> tap_tx_offload_get_port_capa() could be removed.
> 
> Instead of removing the functions I think you can keep them but return
> correct values, in this case return empty, this will make the exiting validation
> functions correct.
> 
> Can you send a fix for that?
> If no fix sent, I suggest going with this patch to remove queue level offload
> support until it is fixed.
> 
> >
> > Please find more comments inline.
> >
> >> -----Original Message-----
> >> From: Ferruh Yigit [mailto:ferruh.yigit at intel.com]
> >> Sent: Tuesday, April 24, 2018 8:54 PM
> >> To: Pascal Mazon <pascal.mazon at 6wind.com>
> >> Cc: dev at dpdk.org; Ferruh Yigit <ferruh.yigit at intel.com>; Mordechay
> >> Haimovsky <motih at mellanox.com>; Ophir Munk
> <ophirmu at mellanox.com>
> >> Subject: [PATCH v3] net/tap: remove queue specific offload support
> >>
> >> It is not clear if tap PMD supports queue specific offloads, removing
> >> the related code.
> >>
> >> Fixes: 95ae196ae10b ("net/tap: use new Rx offloads API")
> >> Fixes: 818fe14a9891 ("net/tap: use new Tx offloads API")
> >> Cc: motih at mellanox.com
> >>
> >> Signed-off-by: Ferruh Yigit <ferruh.yigit at intel.com>
> >> ---
> >> Cc: Ophir Munk <ophirmu at mellanox.com>
> >>
> >> v2:
> >> * rebased
> >>
> >> v3:
> >> * txq->csum restored,
> >>   - ETH_TXQ_FLAGS_IGNORE check removed since ethdev layer takes care
> >> of it
> >>   - tx_conf != NULL check removed, this is internal api who calls this is
> >>   ethdev and it doesn't pass null tx_conf
> >> ---
> >>  drivers/net/tap/rte_eth_tap.c | 102
> >> +++++-------------------------------------
> >>  1 file changed, 10 insertions(+), 92 deletions(-)
> >>
> >> diff --git a/drivers/net/tap/rte_eth_tap.c
> >> b/drivers/net/tap/rte_eth_tap.c index ef33aace9..61b4b5df3 100644
> >> --- a/drivers/net/tap/rte_eth_tap.c
> >> +++ b/drivers/net/tap/rte_eth_tap.c
> >> @@ -278,31 +278,6 @@ tap_rx_offload_get_port_capa(void)
> >>  	       DEV_RX_OFFLOAD_CRC_STRIP;
> >>  }
> >>
> >> -static uint64_t
> >> -tap_rx_offload_get_queue_capa(void)
> >> -{
> >> -	return DEV_RX_OFFLOAD_SCATTER |
> >> -	       DEV_RX_OFFLOAD_IPV4_CKSUM |
> >> -	       DEV_RX_OFFLOAD_UDP_CKSUM |
> >> -	       DEV_RX_OFFLOAD_TCP_CKSUM |
> >> -	       DEV_RX_OFFLOAD_CRC_STRIP;
> >> -}
> >> -
> >
> > TAP PMD supports all of these RX queue specific offloads. I suggest to
> leave this function in place.
> >
> >> -static bool
> >> -tap_rxq_are_offloads_valid(struct rte_eth_dev *dev, uint64_t offloads) -
> {
> >> -	uint64_t port_offloads = dev->data->dev_conf.rxmode.offloads;
> >> -	uint64_t queue_supp_offloads = tap_rx_offload_get_queue_capa();
> >> -	uint64_t port_supp_offloads = tap_rx_offload_get_port_capa();
> >> -
> >> -	if ((offloads & (queue_supp_offloads | port_supp_offloads)) !=
> >> -	    offloads)
> >> -		return false;
> >> -	if ((port_offloads ^ offloads) & port_supp_offloads)
> >> -		return false;
> >> -	return true;
> >> -}
> >> -
> >
> > Putting aside the fact that queue offloads equals port offloads (so could
> ignore "port_supp_offload" variable) - this function is essential to validate
> that the configured Rx offloads are supported by TAP. I suggest to leave this
> function in place.
> > Without it - testpmd falsely confirms non supported offloads.
> > For example before this patch: offloading "hw-vlan-filter" will fail as
> expected:
> >
> > testpmd> port config all
> > testpmd> port config all hw-vlan-filter on port start all
> > Configuring Port 0 (socket 0)
> > PMD: net_tap0: 0x1209fc0: TX configured queues number: 1
> > PMD: net_tap0: 0x1209fc0: RX configured queues number: 1
> > PMD: 0x1209fc0: Rx queue offloads 0x120e don't match port offloads
> > 0x120e or supported offloads 0x300e Fail to configure port 0 rx queues
> >
> > However, with this patch this configuration is falsely accepted.
> >
> >>  /* Callback to handle the rx burst of packets to the correct interface and
> >>   * file descriptor(s) in a multi-queue setup.
> >>   */
> >> @@ -411,31 +386,6 @@ tap_tx_offload_get_port_capa(void)
> >>  	       DEV_TX_OFFLOAD_TCP_CKSUM;
> >>  }
> >>
> >> -static uint64_t
> >> -tap_tx_offload_get_queue_capa(void)
> >> -{
> >> -	return DEV_TX_OFFLOAD_MULTI_SEGS |
> >> -	       DEV_TX_OFFLOAD_IPV4_CKSUM |
> >> -	       DEV_TX_OFFLOAD_UDP_CKSUM |
> >> -	       DEV_TX_OFFLOAD_TCP_CKSUM;
> >> -}
> >> -
> >
> > TAP PMD supports all of these TX queue specific offloads. I suggest to
> leave this function in place.
> >
> >> -static bool
> >> -tap_txq_are_offloads_valid(struct rte_eth_dev *dev, uint64_t offloads) -
> {
> >> -	uint64_t port_offloads = dev->data->dev_conf.txmode.offloads;
> >> -	uint64_t queue_supp_offloads = tap_tx_offload_get_queue_capa();
> >> -	uint64_t port_supp_offloads = tap_tx_offload_get_port_capa();
> >> -
> >> -	if ((offloads & (queue_supp_offloads | port_supp_offloads)) !=
> >> -	    offloads)
> >> -		return false;
> >> -	/* Verify we have no conflict with port offloads */
> >> -	if ((port_offloads ^ offloads) & port_supp_offloads)
> >> -		return false;
> >> -	return true;
> >> -}
> >> -
> >
> > This function is essential to validate that the configured Tx offloads are
> supported by TAP.
> > I suggest to leave this function in place.
> >
> >>  static void
> >>  tap_tx_offload(char *packet, uint64_t ol_flags, unsigned int l2_len,
> >>  	       unsigned int l3_len)
> >> @@ -763,12 +713,10 @@ tap_dev_info(struct rte_eth_dev *dev, struct
> >> rte_eth_dev_info *dev_info)
> >>  	dev_info->max_tx_queues = RTE_PMD_TAP_MAX_QUEUES;
> >>  	dev_info->min_rx_bufsize = 0;
> >>  	dev_info->speed_capa = tap_dev_speed_capa();
> >> -	dev_info->rx_queue_offload_capa =
> >> tap_rx_offload_get_queue_capa();
> >> -	dev_info->rx_offload_capa = tap_rx_offload_get_port_capa() |
> >> -				    dev_info->rx_queue_offload_capa;
> >> -	dev_info->tx_queue_offload_capa =
> >> tap_tx_offload_get_queue_capa();
> >> -	dev_info->tx_offload_capa = tap_tx_offload_get_port_capa() |
> >> -				    dev_info->tx_queue_offload_capa;
> >> +	dev_info->rx_offload_capa = tap_rx_offload_get_port_capa();
> >> +	dev_info->tx_offload_capa = tap_tx_offload_get_port_capa();
> >> +	dev_info->rx_queue_offload_capa = 0;
> >> +	dev_info->tx_queue_offload_capa = 0;
> >>  }
> >>
> >
> > Rx_queue_offloads_capa should be reported as before:
> > dev_info->tx_queue_offload_capa = tap_tx_offload_get_queue_capa();
> > Same for TX offloads.
> >
> > Port capabilities could return queue capabilities:
> >
> > Instead of:
> >
> > dev_info->rx_offload_capa = tap_rx_offload_get_port_capa() |
> > 				    dev_info->rx_queue_offload_capa;
> >
> > We could return:
> >
> > dev_info->rx_offload_capa = dev_info->rx_queue_offload_capa;
> >
> > The same argument is valid for Tx as well.
> >
> >>  static int
> >> @@ -1094,19 +1042,6 @@ tap_rx_queue_setup(struct rte_eth_dev *dev,
> >>  		return -1;
> >>  	}
> >>
> >> -	/* Verify application offloads are valid for our port and queue. */
> >> -	if (!tap_rxq_are_offloads_valid(dev, rx_conf->offloads)) {
> >> -		rte_errno = ENOTSUP;
> >> -		RTE_LOG(ERR, PMD,
> >> -			"%p: Rx queue offloads 0x%" PRIx64
> >> -			" don't match port offloads 0x%" PRIx64
> >> -			" or supported offloads 0x%" PRIx64 "\n",
> >> -			(void *)dev, rx_conf->offloads,
> >> -			dev->data->dev_conf.rxmode.offloads,
> >> -			(tap_rx_offload_get_port_capa() |
> >> -			 tap_rx_offload_get_queue_capa()));
> >> -		return -rte_errno;
> >> -	}
> >
> > The tap_rxq_are_offloads_valid() call is essential. I suggest to leave it in
> place.
> > The RTE_LOG could drop port references to become:
> >
> > 		RTE_LOG(ERR, PMD,
> > 			"%p: Rx queue offloads 0x%" PRIx64
> > 			" don't match"
> > 			" supported offloads 0x%" PRIx64 "\n",
> > 			(void *)dev, rx_conf->offloads,
> > 			 tap_rx_offload_get_queue_capa()));
> >
> >
> >>  	rxq->mp = mp;
> >>  	rxq->trigger_seen = 1; /* force initial burst */
> >>  	rxq->in_port = dev->data->port_id;
> >> @@ -1175,29 +1110,12 @@ tap_tx_queue_setup(struct rte_eth_dev
> *dev,
> >>  		return -1;
> >>  	dev->data->tx_queues[tx_queue_id] = &internals->txq[tx_queue_id];
> >>  	txq = dev->data->tx_queues[tx_queue_id];
> >> -	/*
> >> -	 * Don't verify port offloads for application which
> >> -	 * use the old API.
> >> -	 */
> >> -	if (tx_conf != NULL &&
> >> -	    !!(tx_conf->txq_flags & ETH_TXQ_FLAGS_IGNORE)) {
> >> -		if (tap_txq_are_offloads_valid(dev, tx_conf->offloads)) {
> >> -			txq->csum = !!(tx_conf->offloads &
> >> -					(DEV_TX_OFFLOAD_IPV4_CKSUM |
> >> -					 DEV_TX_OFFLOAD_UDP_CKSUM |
> >> -					 DEV_TX_OFFLOAD_TCP_CKSUM));
> >> -		} else {
> >> -			rte_errno = ENOTSUP;
> >> -			RTE_LOG(ERR, PMD,
> >> -				"%p: Tx queue offloads 0x%" PRIx64
> >> -				" don't match port offloads 0x%" PRIx64
> >> -				" or supported offloads 0x%" PRIx64,
> >> -				(void *)dev, tx_conf->offloads,
> >> -				dev->data->dev_conf.txmode.offloads,
> >> -				tap_tx_offload_get_port_capa());
> >> -			return -rte_errno;
> >> -		}
> >> -	}
> >> +
> >
> > The tap_txq_are_offloads_valid() call is essential. I suggest to leave it in
> place.
> > The RTE_LOG message could drop comparison between queue and port
> capabilities:
> >
> > 			RTE_LOG(ERR, PMD,
> > 				"%p: Tx queue offloads 0x%" PRIx64
> > 				" don't match"
> > 				" supported offloads 0x%" PRIx64,
> > 				(void *)dev, tx_conf->offloads,
> > 				tap_tx_offload_get_queue_capa());
> >
> >> +	txq->csum = !!(tx_conf->offloads &
> >> +			(DEV_TX_OFFLOAD_IPV4_CKSUM |
> >> +			 DEV_TX_OFFLOAD_UDP_CKSUM |
> >> +			 DEV_TX_OFFLOAD_TCP_CKSUM));
> >> +
> >>  	ret = tap_setup_queue(dev, internals, tx_queue_id, 0);
> >>  	if (ret == -1)
> >>  		return -1;
> >> --
> >> 2.14.3
> >