On Fri, Jun 16, 2023 at 1:17 PM Mattias Rönnblom <mattias.ronnb...@ericsson.com> wrote: > > The purpose of the event dispatcher is to help reduce coupling in an > Eventdev-based DPDK application. > > In addition, the event dispatcher also provides a convenient and > flexible way for the application to use service cores for > application-level processing. > > Signed-off-by: Mattias Rönnblom <mattias.ronnb...@ericsson.com> > Tested-by: Peter Nilsson <peter.j.nils...@ericsson.com> > Reviewed-by: Heng Wang <heng.w...@ericsson.com>
Adding eventdev maintainers and tech board, Hi Mattais, Finally, got some time to review this series, and thanks for excellent documentation. I understand the use case for the dispatcher, But following are some of my concern 1) To decouple the application specific business logic, one need to use two function pointers to access per packet (match and process) function. 2) Need to enforce service core for its usage. IMO, Both are a given application's choice, All the application does not need to use this scheme. Keeping the code in lib/eventdev has the following issue. 1)It is kind of enforcing above scheme for all the application modeling, which may not applicable for application use cases and eventdev device does not dictate a specific framework model. 2) The framework code, we never kept in device class library. i.e., public APIs are implemented through device class API and public API don't have any no hook to PMD API. For example, we never kept lib/distributor/ code in lib/ethdev. Other than the placement of this code, I agree with use case and solution at high level . The following could option for placement of this library. Based on that, we can have next level review. 1) It is possible to plug in this to lib/graph by adding new graph model(@zhirun....@intel.com recently added RTE_GRAPH_MODEL_MCORE_DISPATCH) Based on my understanding, That can translate to a) Adding new graph model which allows to have it on graph walk (Graph walk is nothing but calling registered dispatcher routines) b) It is possible to add model specific APIs via rte_graph_model_model_name_xxxx() c) Graph library is not using match callback kind of scheme. Instead, nodes will process the packet and find its downstream node and enqueue to it and then graph_walk() calls the downstream node specific process function. With that, we can meet the original goal of business logic decoupling. However, Currently, nodes are not aware of what kind of graph model it is running, that could be one issue here as eventdev has more scheduling properties like schedule type etc., to overcome that issue, it may be possible to introduce nodes to graph model compatibility (where nodes can advertise the supported graph models) d) Currently we are planning to make graph API as stable, if we are taking this path, we need to hold https://patches.dpdk.org/project/dpdk/patch/20230810180515.113700-1-step...@networkplumber.org/ as we may need to update some public APIs. 2) Have new library lib/event_dispatcher 3) Move to example directory to showcase the framework 4) Move to app/test-eventdev directory to show the case of the framework. Thoughts?
