> From: Ferruh Yigit [mailto:ferruh.yi...@amd.com] > Sent: Sunday, 6 October 2024 22.51 > > On 10/4/2024 9:40 PM, Stephen Hemminger wrote: > > ... > >>>>> The stats queue mapping was a feature that was hinted at being > removed. > >>>>> It only exists because of HW limitations on Intel ixgbe NIC and > SW > >>>>> limitations from RTE_ETHDEV_QUEUE_STAT_CNTRS. > >>>>> > >>>> > >>>> > >>>> We have a plan to remove 'RTE_ETHDEV_QUEUE_STAT_CNTRS', by moving > queue > >>>> stats to xstats. > >>>> > >>>> But ixgbe limitation is there. > >>>> > >>>>> Perhaps there should be a generic SW emulation for this the > mapping? > >>>>> > >>>> > >>>> Ack, cc'ed Bruce. > >>>> But I am not sure ROI of the effort at this stage. > >>> > >>> Not sure what the specific ask for me is here. :-) Overall, I think > moving > >>> queue stats to xstats is the best way to go. > >>> > >> > >> cc'ed because of "generic SW emulation" comment. > >> > >> I was thinking if this mapping can be done transparent to the user > by > >> driver mapping queue <-> stats_register before reading stats, but > @Bruce > >> let me know this won't work because the stats tracking only happens > >> after the mapping. > >> > >> @Stephen, do you have something specific in your mind for SW > emulation > >> for mapping? > > > > Probably not worth doing mapping tables for SW drivers. > > > > My preference would be something like: > > 1. Introduce new API's rte_ethdev_get_queue_stats() and > rte_ethdev_reset_queue_stats(). > > with callbacks in ethdev ops. > > if driver does not support this, then do a shim in ethdev > that uses old stats fields. > > 2. Mark the stats mapping API's as deprecated and always > return error. > > Making special case for ixgbe at this point really is not > worth maintaining. > > 3. After all drivers converted over, drop the fields in > ethdev stats for queues. > > And fix the examples, etc. Yes this would be a big API > change. > > > > Would take a year to get done (ie 25.11). > > > > The problem with existing a API, 'rte_eth_stats_get()', is it has queue > stats fixed sized array which limits us also for some cases causes > unnecessary memory consumption. > > Our solution for now is move queue stats to xstats, as it is flexible > this solves the problem, but as you said in other thread xstats is free > form and may be hard for the application to use it. > > One option is we can add some more data to the xstats, to help > application to consume it easier, like number of queues just before the > queue stats and define queue stats formatting syntax. > > But if we will go with API option, instead of adding new queue stats > ('rte_ethdev_get_queue_stats()'), we can update the existing > 'rte_eth_stats_get()' to return dynamic number of queue stats.
Some users might not care about queue stats, so let's remove them entirely from rte_eth_stats_get(), and put them elsewhere. > > And we need to find someone to own this task. > > > Above is for queue stats, it does not solve the mapping issue, as we > need it for a few drivers and we already have the APIs, I am for just > keeping them as it is, they are not causing any burden to us.
