12/10/2020 17:56, Ananyev, Konstantin: > > From: Ananyev, Konstantin <konstantin.anan...@intel.com> > > > > 12/10/2020 11:56, Slava Ovsiienko: > > > > > We have two approaches how to specify multiple segments to split Rx > > > packets: > > > > > 1. update queue configuration structure 2. introduce new > > > > > rx_queue_setup_ex() routine with extra parameters. > > > > > > > > > > For [1] my only actual dislike is that we would have multiple places > > > > > to specify the pool - in rx_queue_setup() and in the config > > > > > structure. So, we should implement some checking (if we have offload > > > > > flag set we should check whether mp parameter is NULL and segment > > > > > descriptions array pointer/size is provided, if no offload flag set - > > > > > we must > > > check the description array is empty). > > > > > > > > > > > @Thomas, @Ferruh: I'd like to hear what other ethdev maintainers > > > > > > think about it. > > > > > > > > > > Yes, it would be very nice to hear extra opinions. Do we think the > > > > > providing of extra API function is worse than extending existing > > > > > structure, introducing some conditional ambiguity and complicating > > > > > the parameter compliance check? > > > > > > > > Let's try listing pros and cons of each approach, so we can conclude. > > > > > > > > 1/ update queue config struct > > > > > > > > 1.1 pro: keep same queue setup function > > > > 1.2 con: two mempool pointers (struct or function) > > > > 1.3 con: variable size of segment description array > > > > > > > > 2/ new queue setup function > > > > > > > > 2.1 con: two functions for queue setup > > > > 2.2 pro: mempool pointer is not redundant > > > > 2.3 pro: segment description array size defined by the caller > > > > > > > > What else I'm missing? > > > > > > > > > > My 2 cents: can we make new (_ex) function to work for both original > > > config > > > (1 mp for all sizes, no split) and for new config (multiple mp, split > > > allowed)? > > > Then in future (21.11?) we can either get rid of original one, or even > > > make it > > > a wrapper around all one? > > > Konstantin > > > > Yes, actually the mlx5 PMD implementation follows this approach - > > specifying the segment description array with the only element > > and zero size/offset provides exactly the same configuration as existing > > rte_eth_rx_queue_setup(). > > > > Currently I'm detailing the description (how HEAD_ROOM is handled, what > > happens > > if array is shorter the the buffer chain for segment of maximal size, the > > zero segment > > size means follow the value deduced from the pool and so on). > > > > So, may we consider this point as one more "pro" to setup_ex approach ? 😊 > > From my perspective, yes. > It is sort of more gradual approach. > I expect it would be experimental function for some time, > so we'll have time to try it, adjust, fix, etc without breaking original one.
I like the wrapper idea. Is it possible to call rte_eth_rx_queue_setup_ex() from rte_eth_rx_queue_setup() using a rte_eth_rxseg object on the stack?
