Re: [dpdk-dev] [PATCH v2 4/4] app/testpmd: fix displaying Rx Tx queues information

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

On 9/16/2020 10:23 AM, Wei Hu (Xavier) wrote:
> Hi, Ferruh Yigit
> 
> On 2020/9/15 0:31, Ferruh Yigit wrote:
>> On 8/20/2020 2:42 AM, Wei Hu (Xavier) wrote:
>>> From: Huisong Li<lihuisong@huawei.com>
>>>
>>> Currently, the information of Rx/Tx queues from PMD driver is not displayed
>>> exactly in the rxtx_config_display function. Because "ports[pid].rx_conf"
>>> and "ports[pid].tx_conf" maintained in testpmd application may be not the
>>> value actually used by PMD driver. For instance, user does not set a field,
>>> but PMD driver has to use the default value.
>> Overall the question is why testpmd maintains the config values itself?
>> If this is testpmd implementation problem that is no big deal, but if
>> our APIs are forcing applications to maintain local copies that is
>> something to fix I think, which may lead the differences in application
>> copy and more troubles as you are fixing here.
> 
> I think it is a minor problem about displaying some information about 
> testpmd.
> 
> And it has no impact on the usage of application >

Agree this specific issue is minor problem, I already give the review tag.

And if the issue only concerns testpmd, still no big issue.

But I was questioning if this is sign of a design problem in DPDK APIs, 
which matters.

A simple question, why testpmd maintains the local version of the 
configuration?

And follow up can be,
Will it cause any functional problem if application always request 
configs from DPDK when needed instead of maintaining local copies? Are 
we missing APIs to do this?

> 
> Thanks,
> 
> Xavier
> 
>>> This patch fixes rxtx_config_display so that the information of Rx/Tx
>>> queues can be really displayed for the PMD driver that implement
>>> .rxq_info_get and .txq_info_get ops callback function.
>>>
>>> Fixes: 75c530c1bd5351 ("app/testpmd: fix port configuration print")
>>> Fixes: d44f8a485f5d1f ("app/testpmd: enable per queue configure")
>>> Cc:stable@dpdk.org
>>>
>>> Signed-off-by: Huisong Li<lihuisong@huawei.com>
>>> Signed-off-by: Wei Hu (Xavier)<xavier.huwei@huawei.com>
>> Reviewed-by: Ferruh Yigit<ferruh.yigit@intel.com>
>>