Re: [dpdk-dev] [RFC V2 1/2] app/testpmd: fix queue stats mapping configuration

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

Hi Ferruh,

I agree with your proposal. But if we remove record structures, we will
not be able to query the current queue stats mapping configuration. Or
we can provide a query API for the PMD driver that uses the
set_queue_stats_mapping API, and driver records these mapping
information from user.

What do you think?


在 2020/10/31 4:54, Ferruh Yigit 写道:
> On 10/20/2020 9:26 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) There is no need to keep cache line alignment for
>> 'struct queue_stats_mappings'.
>> 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) The configuration result does not take effect or can not be queried
>> in real time.
>>
>> Therefore, we have made the following adjustments:
>> 1) If PMD supports queue stats mapping, configure to driver in real time
>> after executing the command "set stat_qmap rx/tx ...". If not,
>> the command can not be accepted.
>> 2) Only display queues that mapping done by adding a new 'active' field
>>   in queue_stats_mappings struct.
>> 3) Remove cache alignment for 'struct queue_stats_mappings'.
>> 4) Add a new port_stats_mappings struct in rte_port.
>> The struct contains number of rx/txq stats mapping, rx/tx
>> queue_stats_mapping_enabled flag, and rx/tx queue_stats_mapping array.
>> Size of queue_stats_mapping_array is set to "RTE_ETHDEV_QUEUE_STAT_CNTRS"
>>   to ensure that the same number of queues can be set for each port.
>>
> 
> Hi Connor,
> 
> I think above adjustment are good, but after the decision to use xstats 
> for the queue stats, what do you think about more simplification,
> 
> 1)
> What testpmd does is, records the queue stats mapping commands and 
> registers them later on port start & forwarding start.
> What happens if recording and registering completely removed?
> When "set stat_qmap .." issued, it just call the ethdev APIs to do the 
> mapping in device.
> This lets us removing record structures, "struct port_stats_mappings 
> p_stats_map"
> Also can remove 'map_port_queue_stats_mapping_registers()' and its sub 
> functions.
> 
> 2)
> Also lets remove "tx-queue-stats-mapping" & "rx-queue-stats-mapping" 
> parameters, which enables removing 'parse_queue_stats_mapping_config()' 
> function too
> 
> 3)
> Another problem is to display the queue stats, in 'fwd_stats_display()' 
> & 'nic_stats_display()', there is a check if the queue stats mapping 
> enable or not ('rx_queue_stats_mapping_enabled' & 
> 'tx_queue_stats_mapping_enabled'),
> I think displaying queue stats and queue stat mapping should be 
> separate, why not drop checks for queue stats mapping and display queue 
> stats for 'nb_rxq' & 'nb_txq' queues?
> 
> Does above make sense?
> 
> 
> Majority of the drivers doesn't require queue stat mapping to get the 
> queue stats, lets don't pollute main usage with this requirement.
> 
> 
>> 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>
> 
> <...>
> 
> .