On 7/2/2018 4:32 PM, Andrew Rybchenko wrote:
> On 07/02/2018 06:08 PM, Ferruh Yigit wrote:
>> On 6/29/2018 10:44 AM, Jerin Jacob wrote:
>>> The RTE_MAX_ETHPORT_QUEUE_STATS_MAPS does not exists, change
>>> to the correct definition(RTE_ETHDEV_QUEUE_STAT_CNTRS)
>>>
>>> Fixes: 5de201df8927 ("ethdev: add stats per queue")
>>> Cc: sta...@dpdk.org
>>>
>>> Signed-off-by: Jerin Jacob <jerin.ja...@caviumnetworks.com>
>>> ---
>>> lib/librte_ethdev/rte_ethdev.h | 4 ++--
>>> 1 file changed, 2 insertions(+), 2 deletions(-)
>>>
>>> diff --git a/lib/librte_ethdev/rte_ethdev.h b/lib/librte_ethdev/rte_ethdev.h
>>> index 36e3984ea..375ea24ce 100644
>>> --- a/lib/librte_ethdev/rte_ethdev.h
>>> +++ b/lib/librte_ethdev/rte_ethdev.h
>>> @@ -2144,7 +2144,7 @@ void rte_eth_xstats_reset(uint16_t port_id);
>>> * @param stat_idx
>>> * The per-queue packet statistics functionality number that the transmit
>>> * queue is to be assigned.
>>> - * The value must be in the range [0, RTE_MAX_ETHPORT_QUEUE_STATS_MAPS -
>>> 1].
>>> + * The value must be in the range [0, RTE_ETHDEV_QUEUE_STAT_CNTRS - 1].
>> Yes RTE_MAX_ETHPORT_QUEUE_STATS_MAPS doesn't exits and comment is wrong, but
>> RTE_ETHDEV_QUEUE_STAT_CNTRS also slightly not correct.
>>
>> I think how testpmd uses it increase the confusion.
>>
>> In ixgbe there is no stats registers per queue, 128 queues are represented
>> by 16
>> register set. stat_idx here is the index of that 16 registers. You map queue
>> to
>> stats requester to get queue stats.
>>
>> Also there is RTE_ETHDEV_QUEUE_STAT_CNTRS config in the ethdev API, which is
>> the
>> hardcoded size of the queue stats, its default value is 16. This limits
>> number
>> of the queues we can get stats from but saves allocated space. (Why not
>> dynamic?)
>>
>> You can increase the RTE_ETHDEV_QUEUE_STAT_CNTRS to the max supported number
>> of
>> queue and ethdev code will be all valid. But "stat_idx" can't go beyond 16
>> (for
>> ixgbe) because it is hardware limitation and it may change from hw to hw.
>>
>> Also technically it should be possible to reduce RTE_ETHDEV_QUEUE_STAT_CNTRS
>> to
>> a low number, like 2, but in ixgbe map two queues into stat registers 14 & 15
>> and display those two set as queue stat 0 and 1. It seems current
>> implementation
>> prevents this and forces the queues mapped should be less than
>> RTE_ETHDEV_QUEUE_STAT_CNTRS. Overall it seems there is a mixed used of
>> RTE_ETHDEV_QUEUE_STAT_CNTRS and stats queue index values, I assume because
>> both
>> are same values.
>>
>> I suggest updating it as:
>> "
>> The value must be in the range:
>> [0 - MIN(HW Stat Registers Size, RTE_ETHDEV_QUEUE_STAT_CNTRS) - 1]
>> "
>
> Technically I think it is not a problem to specify more than HW supports.
> The function should simply return error. RTE_ETHDEV_QUEUE_STAT_CNTRS is
> a hard limit which should be checked by ethdev.
> The reasonable next question is how to find out what is the maximum for
> PMD/HW.
> I think it deserves entry in dev_info. May be not now.
Yes there is not a way to find out that limit by application, setting
RTE_ETHDEV_QUEUE_STAT_CNTRS to 16 and using it as limit solving the issue for
now :)
> "HW Stats Registers size" is too HW specific. It could be not HW, but the PMD
> limitation and limits for Rx and Tx could be different. So, may be something
> like:
> "Device max per Tx queue stats"
>
>>> * @return
>>> * Zero if successful. Non-zero otherwise.
>>> */
>>> @@ -2164,7 +2164,7 @@ int rte_eth_dev_set_tx_queue_stats_mapping(uint16_t
>>> port_id,
>>> * @param stat_idx
>>> * The per-queue packet statistics functionality number that the receive
>>> * queue is to be assigned.
>>> - * The value must be in the range [0, RTE_MAX_ETHPORT_QUEUE_STATS_MAPS -
>>> 1].
>>> + * The value must be in the range [0, RTE_ETHDEV_QUEUE_STAT_CNTRS - 1].
>>> * @return
>>> * Zero if successful. Non-zero otherwise.
>>> */
>>>
>
