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

[Ophir Munk <ophirmu@mellanox.com>]

Hi Ferruh,
I started working on a patch.
No need for your test example.

> -----Original Message-----
> From: Ophir Munk
> Sent: Wednesday, April 25, 2018 3:00 PM
> To: 'Ferruh Yigit' <ferruh.yigit@intel.com>; Pascal Mazon
> <pascal.mazon@6wind.com>
> Cc: dev@dpdk.org; Mordechay Haimovsky <motih@mellanox.com>; Olga
> Shern <olgas@mellanox.com>; Thomas Monjalon <thomas@monjalon.net>;
> Raslan Darawsheh <rasland@mellanox.com>; Shahaf Shuler
> <shahafs@mellanox.com>
> Subject: RE: [PATCH v3] net/tap: remove queue specific offload support
> 
> 
> 
> > -----Original Message-----
> > From: Ferruh Yigit [mailto:ferruh.yigit@intel.com]
> > Sent: Wednesday, April 25, 2018 12:48 PM
> > To: Ophir Munk <ophirmu@mellanox.com>; Pascal Mazon
> > <pascal.mazon@6wind.com>
> > Cc: dev@dpdk.org; Mordechay Haimovsky <motih@mellanox.com>; Olga
> Shern
> > <olgas@mellanox.com>; Thomas Monjalon <thomas@monjalon.net>;
> Raslan
> > Darawsheh <rasland@mellanox.com>; Shahaf Shuler
> <shahafs@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@intel.com]
> > >> Sent: Tuesday, April 24, 2018 8:54 PM
> > >> To: Pascal Mazon <pascal.mazon@6wind.com>
> > >> Cc: dev@dpdk.org; Ferruh Yigit <ferruh.yigit@intel.com>; Mordechay
> > >> Haimovsky <motih@mellanox.com>; Ophir Munk
> > <ophirmu@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@mellanox.com
> > >>
> > >> Signed-off-by: Ferruh Yigit <ferruh.yigit@intel.com>
> > >> ---
> > >> Cc: Ophir Munk <ophirmu@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
> > >