Re: [dpdk-stable] [PATCH] app/testpmd: fix queue Rx and Tx offload reconfig cmd

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

On 4/12/2021 3:21 AM, Li, Xiaoyun wrote:
> 
> 
>> -----Original Message-----
>> From: Yu, DapengX <dapengx.yu@intel.com>
>> Sent: Friday, April 9, 2021 18:29
>> To: Li, Xiaoyun <xiaoyun.li@intel.com>; Yigit, Ferruh <ferruh.yigit@intel.com>;
>> Zhang, Qi Z <qi.z.zhang@intel.com>
>> Cc: dev@dpdk.org; stable@dpdk.org
>> Subject: RE: [dpdk-stable] [PATCH] app/testpmd: fix queue Rx and Tx offload
>> reconfig cmd
>>
>>
>>
>>> -----Original Message-----
>>> From: Li, Xiaoyun <xiaoyun.li@intel.com>
>>> Sent: Friday, April 9, 2021 3:50 PM
>>> To: Yu, DapengX <dapengx.yu@intel.com>; Yigit, Ferruh
>>> <ferruh.yigit@intel.com>; Zhang, Qi Z <qi.z.zhang@intel.com>
>>> Cc: dev@dpdk.org; stable@dpdk.org
>>> Subject: RE: [dpdk-stable] [PATCH] app/testpmd: fix queue Rx and Tx
>>> offload reconfig cmd
>>>
>>>
>>>
>>>> -----Original Message-----
>>>> From: Yu, DapengX <dapengx.yu@intel.com>
>>>> Sent: Friday, April 9, 2021 13:25
>>>> To: Yigit, Ferruh <ferruh.yigit@intel.com>; Li, Xiaoyun
>>>> <xiaoyun.li@intel.com>; Zhang, Qi Z <qi.z.zhang@intel.com>
>>>> Cc: dev@dpdk.org; stable@dpdk.org
>>>> Subject: RE: [dpdk-stable] [PATCH] app/testpmd: fix queue Rx and Tx
>>>> offload reconfig cmd
>>>>
>>>>
>>>>
>>>>> -----Original Message-----
>>>>> From: Yigit, Ferruh <ferruh.yigit@intel.com>
>>>>> Sent: Thursday, April 8, 2021 11:42 PM
>>>>> To: Yu, DapengX <dapengx.yu@intel.com>; Li, Xiaoyun
>>>>> <xiaoyun.li@intel.com>; Zhang, Qi Z <qi.z.zhang@intel.com>
>>>>> Cc: dev@dpdk.org; stable@dpdk.org
>>>>> Subject: Re: [dpdk-stable] [PATCH] app/testpmd: fix queue Rx and
>>>>> Tx offload reconfig cmd
>>>>>
>>>>> On 4/1/2021 9:28 AM, dapengx.yu@intel.com wrote:
>>>>>> From: Dapeng Yu <dapengx.yu@intel.com>
>>>>>>
>>>>>> Configure per queue rx offloading and per queue tx offloading
>>>>>> command shouldn't trigger the rte_eth_dev_configure() to
>>>>>> reconfigure
>>>> device.
>>>>>>
>>>>>> The patch sets the queue reconfiguration flag only, and does not
>>>>>> set the device reconfiguration flag. Therefore after port is
>>>>>> restarted,
>>>>>> rte_eth_dev_configure() will not be called again.
>>>>>>
>>>>>
>>>>> Just to clarify the impact, was calling 'rte_eth_dev_configure()'
>>>>> causing any problem, is this fixing any issue?
>>>>> Or is this patch an optimization to eliminate an unnecessary call?
>>>>>
>>>> This patch does fix an issue, and it also eliminates an unnecessary call.
>>>>
>>>> The issue is:
>>>> per-queue configuration, for example: port 0 rxq 0 rx_offload
>>>> jumbo_frame off triggers the per-device configuration change: the
>>>> RSS key is reconfigured and changes after rte_eth_dev_configure() is
>>>> called on ICE PMD driver, that cause a test case failure.
>>>>
>>>
>>> Hmmm. I agree on the following. It doesn't need dev_configure. That's
>>> why I give you ack.
>>>
>>> But your issue. Shouldn't you fix the driver? The vsi->rss_key[] just
>>> updated itself as a random value when dev_conf doesn't contain one.
>>> But your case is dev_conf doesn't contain new rss key, but
>>> vsi->rss_key is not null. In this case, it should keep the same not get a new
>> random key.
>>>
>> In current implementation, dev->data->dev_conf.rx_adv_conf.rss_conf in PMD
>> does not hold the rss_key value if user does not set it in the input parameter of
>> rte_eth_dev_configure().
>>
>> Even if PMD generate one automatically, it will not be saved in dev->data-
>>> dev_conf.rx_adv_conf.rss_conf.
>>
>> When user want to get rss_key, it will be retrieved on the fly from hardware, but
>> not from any variable in PMD.
>>
>> So PMD (ice and i40e) think only rss_key  which is set by user via
>> rte_eth_dev_configure() can be reused when port is reconfigured.
>>
>> If it is not present, PMD will generate one by itself anyway even if it is present in
>> vsi->rss_key.
>>
>> I don’t think this behavior is wrong, so did not fix ice PMD.
> 
> If you want to recover the rss key. The driver should store the key in vsi->rss_key also in ice_rss_hash_update(). Then when user not config rss_key in rss_conf and vs->rss_key is not 0, you should set the original value not a random value to hw.
> 

+1

> Otherwise, you are assuming the behavior rss to different queues is right since user want random key. It's not an issue.
> 
> Any scenario, it's not testpmd issue. Please withdraw your patch.
> 
>>
>>>> There is an unnecessary call in original implementation because both
>>>> cmd_config_per_queue_rx_offload_parsed() and
>>>> cmd_config_per_queue_tx_offload_parsed()
>>>> does not update the "port->dev_conf" which hold the port
>>>> configuration, therefore there is no need to call rte_eth_dev_configure().
>