> From: Ferruh Yigit [mailto:ferruh.yi...@amd.com] > Sent: Monday, 6 March 2023 13.49 > > On 1/4/2023 8:21 AM, Morten Brørup wrote: > >> From: Feifei Wang [mailto:feifei.wa...@arm.com] > >> Sent: Wednesday, 4 January 2023 08.31 > >> > >> Add 'tx_fill_sw_ring' and 'rx_flush_descriptor' API into direct rearm > >> mode for separate Rx and Tx Operation. And this can support different > >> multiple sources in direct rearm mode. For examples, Rx driver is > >> ixgbe, > >> and Tx driver is i40e. > >> > >> Suggested-by: Honnappa Nagarahalli <honnappa.nagaraha...@arm.com> > >> Suggested-by: Ruifeng Wang <ruifeng.w...@arm.com> > >> Signed-off-by: Feifei Wang <feifei.wa...@arm.com> > >> Reviewed-by: Ruifeng Wang <ruifeng.w...@arm.com> > >> Reviewed-by: Honnappa Nagarahalli <honnappa.nagaraha...@arm.com> > >> --- > > > > This feature looks very promising for performance. I am pleased to see > progress on it. > > > > Hi Morten, > > Yes it brings some performance, but not to generic use case, only to > specific and constraint use case.
I got the impression that the supported use case is a prominent and important use case. This is the primary argument for considering such a complex non-generic feature. > > And changes are relatively invasive comparing the usecase it supports, > like it adds new two inline datapath functions and a new dev_ops. > > I am worried the unnecessary complexity and possible regressions in the > fundamental and simple parts of the project, with a good intention to > gain a few percentage performance in a specific usecase, can hurt the > project. > > > I can see this is compared to MBUF_FAST_FREE feature, but MBUF_FAST_FREE > is just an offload benefiting from existing offload infrastructure, > which requires very small update and logically change in application and > simple to implement in the drivers. So, they are not same from > complexity perspective. > > Briefly, I am not comfortable with this change, I would like to see an > explicit approval and code review from techboard to proceed. I agree that the complexity is very high, and thus requires extra consideration. Your suggested techboard review and approval process seems like a good solution. And the performance benefit of direct rearm should be compared to the performance using the new zero-copy mempool API. -Morten
