On Wed, Jan 25, 2023 at 10:02 PM Naga Harish K, S V <s.v.naga.haris...@intel.com> wrote: > > > > > -----Original Message----- > > From: Jerin Jacob <jerinjac...@gmail.com>
> > > > > > > > > > > > + */ > > > > > > > + uint32_t rsvd[15]; > > > > > > > + /**< Reserved fields for future use */ > > > > > > > > > > > > Introduce rte_event_eth_rx_adapter_runtime_params_init() to > > make > > > > > > sure rsvd is zero. > > > > > > > > > > > > > > > > The reserved fields are not used by the adapter or application. > > > > > Not sure Is it necessary to Introduce a new API to clear reserved > > > > > fields. > > > > > > > > When adapter starts using new fileds(when we add new fieds in > > > > future), the old applicaiton which is not using > > > > rte_event_eth_rx_adapter_runtime_params_init() may have junk value > > > > and then adapter implementation will behave bad. > > > > > > > > > > > > > > does it mean, the application doesn't re-compile for the new DPDK? > > > > Yes. No need recompile if ABI not breaking. > > > > > When some of the reserved fields are used in the future, the application > > also may need to be recompiled along with DPDK right? > > > As the application also may need to use the newly consumed reserved > > fields? > > > > The problematic case is: > > > > Adapter implementation of 23.07(Assuming there is change params) field > > needs to work with application of 23.03. > > rte_event_eth_rx_adapter_runtime_params_init() will sove that. > > > > As rte_event_eth_rx_adapter_runtime_params_init() initializes only reserved > fields to zero, it may not solve the issue in this case. rte_event_eth_rx_adapter_runtime_params_init() needs to zero all fields, not just reserved field. The application calling sequence is struct my_config c; rte_event_eth_rx_adapter_runtime_params_init(&c) c.interseted_filed_to_be_updated = val; Let me share an example and you can tell where is the issue 1)Assume parameter structure is 64B and for 22.03 8B are used. 2)rte_event_eth_rx_adapter_runtime_params_init() will clear all 64B. 3)There is an application written based on 22.03 which using only 8B after calling rte_event_eth_rx_adapter_runtime_params_init() 4)Assume, in 22.07 another 8B added to structure. 5)Now, the application (3) needs to run on 22.07. Since the application is calling rte_event_eth_rx_adapter_runtime_params_init() and 9 to 15B are zero, the implementation will not go bad. > The old application only tries to set/get previous valid fields and the newly > used fields may still contain junk value. > If the application wants to make use of any the newly used params, the > application changes are required anyway. Yes. If application wants to make use of newly added features. No need to change if new features are not needed for old application.
