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

Ferruh Yigit ferruh.yigit at intel.com
Wed Apr 25 11:48:13 CEST 2018


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.
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
> testpmd> 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
> 



More information about the dev mailing list