From: Gaëtan Rivet, Monday, January 8, 2018 4:22 PM > On Mon, Jan 08, 2018 at 01:55:52PM +0000, Matan Azrad wrote: > > Hi Gaetan > > > > From: Gaëtan Rivet, Monday, January 8, 2018 3:30 PM > > > On Mon, Jan 08, 2018 at 12:30:19PM +0000, Matan Azrad wrote: > > > > > > > > > > > > From: Gaëtan Rivet, Monday, January 8, 2018 1:40 PM > > > > > Hi Matan, > > > > > > > > > > On Sun, Jan 07, 2018 at 09:45:51AM +0000, Matan Azrad wrote: > > > > > > Testpmd should not use ethdev ports which are managed by other > > > > > > DPDK entities. > > > > > > > > > > > > Set Testpmd ownership to each port which is not used by other > > > > > > entity and prevent any usage of ethdev ports which are not > > > > > > owned by > > > Testpmd. > > > > > > > > > > > > > > > > This patch should not be necessary. > > > > > > > > > > Ideally, your API evolution should not impact the default case. > > > > > As such, the default iterator RTE_ETH_FOREACH_DEV should still > > > > > be used in > > > testpmd. > > > > > > > > > Why? We want to adjust testpmd to the port ownership. > > > > > > > > > > This adjustment should be seamless for existing application. > > > > > > > > RTE_ETH_FOREACH_DEV should call > > > RTE_ETH_FOREACH_DEV_OWNED_BY, with > > > > > the default owner (meaning that it would thus iterate on the > > > > > application-owned set of device). > > > > > > > > > > > > > It will break the API (we already talked about it). > > > > There is not any default owner: > > > > Any DPDK entity includes applications must to allocate an owner ID > > > > and use > > > it to own the ports they wants to use. > > > > The application can include more than 1 owner depends on the user > needs. > > > > Each DPDK entity which can synchronize all its port usage can be a > > > > valid > > > DPDK entity for the ownership mechanism. > > > > > > > > > > That's the point of my remark: you did not include a default owner. > > > I think there should be one, and that all ports should pertain to > > > this default owner by default when created. > > > > > > This would not prevent a user or application from adding new owners > > > specific to their use and specialize ports if need be. > > > > > > However, for other applications that do not care for this > > > specialization, they should run with the current API and avoid the > > > ports that are configured by other third parties. > > > > > > > RTE_ETH_FOREACH_DEV means iterate over all devices and should stay as > is in my opinion. > > I understand your concern about changes in current application, But > > your "default" suggestion will cause to "non-default" applications to reset > all the default owners and will complicate them and hurt semantics. > > Why should an application be able to iterate over all ports? Leave this > capability to the EAL (or ethdev layer) alone, while other components should > be restricted to their specific set. >
Yes, you right. > And if a need for this general iterator appears, solutions could be found very > easily. > > RTE_ETH_FOREACH_DEV currently does not iterate over deferred ports, it > iterates over the base set of ports available. Changing this behavior is not > necessary, you could introduce your API while keeping it. > Right. > > > > > I'm thinking about applications already written that would be used > > > with fail- safe ports: they would use RTE_ETH_FOREACH_DEV, and would > > > thus iterate over every ports, including those owned by the > > > fail-safe, unless they start following the new API. > > > > > > > They should start, it is really not complicated. > > The point is not whether developpers downstream would be able to grasp > such complexity, but whether a project like DPDK should foster an unstable > environment for its currently still limited ecosystem. > > > What's about application which use count=rte_eth_dev_count and iterate > over all ports from 0 to count-1? > > We cannot save all the wrong application options. > > > > > This is unnecessary: adding a default owner for all created ports > > > and redefining RTE_ETH_FOREACH_DEV as follow > > > > > > #define RTE_ETH_FOREACH_DEV(i) > > > RTE_ETH_FOREACH_DEV_OWNED_BY(i, RTE_ETH_DEFAULT_OWNER) > > > > > > Is simple enough and will simplify the work of DPDK users. Moreover, > > > it would make fail-safe compatible with all applications using > > > RTE_ETH_FOREACH_DEV without additional evolution. It would actually > > > make any code using your API supported by those same applications, > > > which I think would help its adoption. > > > > > > > Will break API, will hurt semantic of FOREACH , and will complicate > ownership care applications as I wrote above. > > Well, breaking an API is best before such API is integrated anyway. > > I disagree regarding the added complexity for applications that would use > ownership. With your proposal, most applications will only add a single user > and register all their ports with this user, then be forced to iterate upon > their > registered user. > > You can save all of them the hassle of adding this code, by taking care of the > most common case, avoiding redundant code downstream and simplifying > possible future update to this default case. > > So if anything, this would greatly simplify ownership for the vast majority of > applications. > OK, got you. I will just document the API with the new semantic and will use the NO_OWNER for the old API. But actually I think testpmd should use the ownership mechanism as a good example for it. Thanks! > -- > Gaëtan Rivet > 6WIND
