Re: [dpdk-dev] [RFC V4] app/testpmd: fix queue stats mapping configuration

["Min Hu (Connor)" <humin29@huawei.com>]

在 2020/11/21 12:29, Stephen Hemminger 写道:
> On Fri, 20 Nov 2020 23:33:40 +0000
> Ferruh Yigit <ferruh.yigit@intel.com> wrote:
> 
>> On 11/20/2020 11:21 PM, Stephen Hemminger wrote:
>>> On Fri, 20 Nov 2020 17:26:55 +0000
>>> Ferruh Yigit <ferruh.yigit@intel.com> wrote:
>>>    
>>>> On 11/20/2020 11:50 AM, Min Hu (Connor) wrote:
>>>>> From: Huisong Li <lihuisong@huawei.com>
>>>>>
>>>>> Currently, the queue stats mapping has the following problems:
>>>>> 1) Many PMD drivers don't support queue stats mapping. But there is no
>>>>>     failure message after executing the command "set stat_qmap rx 0 2 2".
>>>>> 2) Once queue mapping is set, unrelated and unmapped queues are also
>>>>> displayed.
>>>>> 3) The configuration result does not take effect or can not be queried
>>>>> in real time.
>>>>> 4) The mapping arrays, "tx_queue_stats_mappings_array" &
>>>>> "rx_queue_stats_mappings_array" are global and their sizes are based on
>>>>> fixed max port and queue size assumptions.
>>>>> 5) These record structures, 'map_port_queue_stats_mapping_registers()'
>>>>>     and its sub functions are redundant for majority of drivers.
>>>>> 6) The display of the queue stats and queue stats mapping is mixed
>>>>>     together.
>>>>>
>>>>> Since xstats is used to obtain queue statistics, we have made the following
>>>>>     simplifications and adjustments:
>>>>> 1) If PMD requires and supports queue stats mapping, configure to driver in
>>>>>     real time by calling ethdev API after executing the command
>>>>>     "set stat_qmap rx/tx ...". If not, the command can not be accepted.
>>>>> 2) Based on the above adjustments, these record structures,
>>>>> 'map_port_queue_stats_mapping_registers()' and its sub functions can be
>>>>>     removed. "tx-queue-stats-mapping" & "rx-queue-stats-mapping" parameters,
>>>>>     and 'parse_queue_stats_mapping_config()' can be removed too.
>>>>> 3) remove display of queue stats mapping in 'fwd_stats_display()' &
>>>>>     'nic_stats_display()', and obtain queue stats by xstats.
>>>>>     Since the record structures are removed, 'nic_stats_mapping_display()'
>>>>>     can be deleted.
>>>>>
>>>>> Fixes: 4dccdc789bf4b ("app/testpmd: simplify handling of stats mappings error")
>>>>> Fixes: 013af9b6b64f6 ("app/testpmd: various updates")
>>>>> Fixes: ed30d9b691b21 ("app/testpmd: add stats per queue")
>>>>>
>>>>> Signed-off-by: Huisong Li <lihuisong@huawei.com>
>>>>
>>>> Overall	looks good to me.
>>>> I did a quick test didn't see anything unexpected. 'xstats' or 'dpdk-proc-info'
>>>> app still can be used to get queue stats and "set stat_qmap ..." is working as
>>>> expected.
>>>>
>>>> But it is a little late for this release cycle, would you be OK to get this at
>>>> the beginning of next release?
>>>
>>> Could we plan to deprecate queue stats mapping in future when xstats work is done?
>>>    
>>
>> Even queue stats moved to xstats, a few PMDs still need this configuration and API.
>> And this patch already cleans the queue stats mapping noise from testpmd.
>>
>> What is the benefit/motivation to deprecate the queue stats mapping API?
> 
> Mostly because so few drivers implement it, that any application using it
> is  going to be non-portable.
>    Hi, Stephen,
	For PMDs with few hardware queue statistics resources, such as
ixgbe, all queue stats are recorded in statistics register 0 by default.
If users want to get detailed queue stats, users have to call the queue
stats mapping API. From this point of view, it is necessary for these
PMDs.


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