Re: [dpdk-dev] [RFC] ethdev: remove all offload API

[Ferruh Yigit <ferruh.yigit@intel.com>]

On 6/11/2018 12:00 PM, Shahaf Shuler wrote:
> Hi Ferruh,
> 
> Thanks for this patch. 
> 
> Monday, June 11, 2018 12:10 PM, Ferruh Yigit:
>> Subject: Re: [RFC] ethdev: remove all offload API
>>
>> On 6/9/2018 9:04 AM, Andrew Rybchenko wrote:
>>> On 06/09/2018 01:41 AM, Ferruh Yigit wrote:
>>>> Cc: Shahaf Shuler <shahafs@mellanox.com>
>>>>
>>>> Signed-off-by: Ferruh Yigit <ferruh.yigit@intel.com>
>>>> ---
>>>
>>> <...>
>>>
>>>> diff --git a/app/test-eventdev/test_perf_common.c
>>>> b/app/test-eventdev/test_perf_common.c
>>>> index d00f91802..9fe042ffe 100644
>>>> --- a/app/test-eventdev/test_perf_common.c
>>>> +++ b/app/test-eventdev/test_perf_common.c
>>>> @@ -680,13 +680,7 @@ perf_ethdev_setup(struct evt_test *test, struct
>> evt_options *opt)
>>>>  			.mq_mode = ETH_MQ_RX_RSS,
>>>>  			.max_rx_pkt_len = ETHER_MAX_LEN,
>>>>  			.split_hdr_size = 0,
>>>> -			.header_split   = 0,
>>>> -			.hw_ip_checksum = 0,
>>>> -			.hw_vlan_filter = 0,
>>>> -			.hw_vlan_strip  = 0,
>>>> -			.hw_vlan_extend = 0,
>>>>  			.jumbo_frame    = 0,
>>>> -			.hw_strip_crc   = 1,
>>>
>>
>> Hi Andrew,
>>
>>> I have 2 questions here:
>>>  1. Why is jumbo_frame kept? There is
>> DEV_RX_OFFLOAD_JUMBO_FRAME.
>>
>> Because there are still some usage of this flag in PMDs, they need to be
>> clarified before removing the flag. I am for removing the flag in final version,
>> but for this RFC I am not able to find enough time to work on PMDs for it.
> 
> Can you elaborate?
> Is this something more than just a replace of the jumbo_frame bit with its corresponding flag? 

That was my concern that copy paste won't be enough because some drivers not
just use the jumbo_frame but set it based on max_rx_pkt_len etc.., that is why
left out .jumbo_frame in the RFC.

> 
>>
>>>  2. Why is hw_strip_crc=1 discarded? Yes, I remember plans to make it
>>>      default behaviour and introduce flag to keep CRC, but right now
>>> the
>>>      patch looks like mixture of two changes which is not good.
>>
>> Yes it is wrong, app should replace "".hw_strip_crc=1 with KEEP_CRC offload.
>> Since both are RFC, kind of hard to maintain, but I think good to create a
>> dependency from this patch to KEEP_CRC one.
>>
>>>
>>> There are more cases in the patch where hw_strip_crc=1 is simply
>> discarded.
>>>
>>> <...>
>>>
>>>> diff --git a/drivers/net/sfc/sfc_ethdev.c
>>>> b/drivers/net/sfc/sfc_ethdev.c index 1b6499f85..ee8ae5b9f 100644
>>>> --- a/drivers/net/sfc/sfc_ethdev.c
>>>> +++ b/drivers/net/sfc/sfc_ethdev.c
>>>> @@ -1089,7 +1089,6 @@ sfc_tx_queue_info_get(struct rte_eth_dev
>> *dev,
>>>> uint16_t tx_queue_id,
>>>>
>>>>  	memset(qinfo, 0, sizeof(*qinfo));
>>>>
>>>> -	qinfo->conf.txq_flags = txq_info->txq->flags;
>>>>  	qinfo->conf.offloads = txq_info->txq->offloads;
>>>>  	qinfo->conf.tx_free_thresh = txq_info->txq->free_thresh;
>>>>  	qinfo->conf.tx_deferred_start = txq_info->deferred_start; diff
>>>> --git a/drivers/net/sfc/sfc_rx.c b/drivers/net/sfc/sfc_rx.c index
>>>> cc76a5b15..58a0df583 100644
>>>> --- a/drivers/net/sfc/sfc_rx.c
>>>> +++ b/drivers/net/sfc/sfc_rx.c
>>>> @@ -1446,7 +1446,6 @@ sfc_rx_check_mode(struct sfc_adapter *sa,
>> struct rte_eth_rxmode *rxmode)
>>>>  	if (~rxmode->offloads & DEV_RX_OFFLOAD_CRC_STRIP) {
>>>>  		sfc_warn(sa, "FCS stripping cannot be disabled - always on");
>>>>  		rxmode->offloads |= DEV_RX_OFFLOAD_CRC_STRIP;
>>>> -		rxmode->hw_strip_crc = 1;
>>>>  	}
>>>>
>>>>  	return rc;
>>>> diff --git a/drivers/net/sfc/sfc_tx.c b/drivers/net/sfc/sfc_tx.c
>>>> index 1bcc2c697..6d42a1a65 100644
>>>> --- a/drivers/net/sfc/sfc_tx.c
>>>> +++ b/drivers/net/sfc/sfc_tx.c
>>>> @@ -171,7 +171,6 @@ sfc_tx_qinit(struct sfc_adapter *sa, unsigned int
>> sw_index,
>>>>  	txq->free_thresh =
>>>>  		(tx_conf->tx_free_thresh) ? tx_conf->tx_free_thresh :
>>>>  		SFC_TX_DEFAULT_FREE_THRESH;
>>>> -	txq->flags = tx_conf->txq_flags;
>>>>  	txq->offloads = offloads;
>>>>
>>>>  	rc = sfc_dma_alloc(sa, "txq", sw_index,
>>>> EFX_TXQ_SIZE(txq_info->entries), @@ -182,7 +181,6 @@
>> sfc_tx_qinit(struct sfc_adapter *sa, unsigned int sw_index,
>>>>  	memset(&info, 0, sizeof(info));
>>>>  	info.max_fill_level = txq_max_fill_level;
>>>>  	info.free_thresh = txq->free_thresh;
>>>> -	info.flags = tx_conf->txq_flags;
>>>>  	info.offloads = offloads;
>>>>  	info.txq_entries = txq_info->entries;
>>>>  	info.dma_desc_size_max = encp->enc_tx_dma_desc_size_max;
>> @@ -431,18
>>>> +429,10 @@ sfc_tx_qstart(struct sfc_adapter *sa, unsigned int sw_index)
>>>>  	if (rc != 0)
>>>>  		goto fail_ev_qstart;
>>>>
>>>> -	/*
>>>> -	 * The absence of ETH_TXQ_FLAGS_IGNORE is associated with a
>> legacy
>>>> -	 * application which expects that IPv4 checksum offload is enabled
>>>> -	 * all the time as there is no legacy flag to turn off the offload.
>>>> -	 */
>>>> -	if ((txq->offloads & DEV_TX_OFFLOAD_IPV4_CKSUM) ||
>>>> -	    (~txq->flags & ETH_TXQ_FLAGS_IGNORE))
>>>> +	if (txq->offloads & DEV_TX_OFFLOAD_IPV4_CKSUM)
>>>>  		flags |= EFX_TXQ_CKSUM_IPV4;
>>>>
>>>> -	if ((txq->offloads & DEV_TX_OFFLOAD_OUTER_IPV4_CKSUM) ||
>>>> -	    ((~txq->flags & ETH_TXQ_FLAGS_IGNORE) &&
>>>> -	     (offloads_supported &
>> DEV_TX_OFFLOAD_OUTER_IPV4_CKSUM)))
>>>> +	if (txq->offloads & DEV_TX_OFFLOAD_OUTER_IPV4_CKSUM)
>>>>  		flags |= EFX_TXQ_CKSUM_INNER_IPV4;
>>>>
>>>>  	if ((txq->offloads & DEV_TX_OFFLOAD_TCP_CKSUM) || @@ -453,16
>> +443,7
>>>> @@ sfc_tx_qstart(struct sfc_adapter *sa, unsigned int sw_index)
>>>>  			flags |= EFX_TXQ_CKSUM_INNER_TCPUDP;
>>>>  	}
>>>>
>>>> -	/*
>>>> -	 * The absence of ETH_TXQ_FLAGS_IGNORE is associated with a
>> legacy
>>>> -	 * application. In turn, the absence of ETH_TXQ_FLAGS_NOXSUMTCP
>> is
>>>> -	 * associated specifically with a legacy application which expects
>>>> -	 * both TCP checksum offload and TSO to be enabled because the
>> legacy
>>>> -	 * API does not provide a dedicated mechanism to control TSO.
>>>> -	 */
>>>> -	if ((txq->offloads & DEV_TX_OFFLOAD_TCP_TSO) ||
>>>> -	    ((~txq->flags & ETH_TXQ_FLAGS_IGNORE) &&
>>>> -	     (~txq->flags & ETH_TXQ_FLAGS_NOXSUMTCP)))
>>>> +	if (txq->offloads & DEV_TX_OFFLOAD_TCP_TSO)
>>>>  		flags |= EFX_TXQ_FATSOV2;
>>>>
>>>>  	rc = efx_tx_qcreate(sa->nic, sw_index, 0, &txq->mem,
>>>
>>> net/sfc changes looks good.
>>> Plus 'struct sfc_txq -> flags' (drivers/net/sfc/sfc_tx.h) and 'struct
>>> sfc_dp_tx_qcreate_info -> flags' (drivers/net/sfc/sfc_dp_tx.h) should
>>> be removed since there are not used now.
>>>
>>> If finally rxmode.jumbo_frame is removed, it should removed from
>>> net/sfc as well (but compiler will help to find it in any case).
>>>
>>> After applying the patch:
>>> $ git grep ETH_TXQ_FLAGS
>>> drivers/net/fm10k/fm10k.h:#define FM10K_SIMPLE_TX_FLAG
>>> ((uint32_t)ETH_TXQ_FLAGS_NOMULTSEGS | \
>>> drivers/net/fm10k/fm10k.h:
>>> ETH_TXQ_FLAGS_NOOFFLOADS)
>>
>> Thanks, will remove this too.
>>
>>>
>>> In general I think that we should do it ASAP. Also it will guarantee
>>> that new PMDs do not use corresponding structure members etc.
>>
>> +1, +1
>