On Wed, Jul 1, 2020 at 2:54 PM Andrey Vesnovaty <andrey.vesnov...@gmail.com> wrote: > > > On Tue, Jun 30, 2020 at 12:52 PM Jerin Jacob <jerinjac...@gmail.com> wrote: >> >> On Mon, Jun 29, 2020 at 3:52 PM Andrey Vesnovaty >> <andrey.vesnov...@gmail.com> wrote: >> > >> > >> > >> > On Sun, Jun 28, 2020 at 4:42 PM Jerin Jacob <jerinjac...@gmail.com> wrote: >> >> >> >> On Sun, Jun 28, 2020 at 2:14 PM Andrey Vesnovaty >> >> <andrey.vesnov...@gmail.com> wrote: >> >> > >> >> > Hi >> >> > >> >> > On Fri, Jun 26, 2020 at 2:44 PM Jerin Jacob <jerinjac...@gmail.com> >> >> > wrote: >> >> >> >> >> >> On Sat, Jun 20, 2020 at 7:02 PM Andrey Vesnovaty >> >> >> <andrey.vesnov...@gmail.com> wrote: >> >> >> > >> >> >> > Hi, and thanks a lot for your RFC v1 comments. >> >> >> > >> >> >> > RFC v2 emphasize the intent for sharing the flow action: >> >> >> > * The term 'action context' was unclear and replaced with >> >> >> > 'shared action'. >> >> >> > * RFC v2 subject became 'add flow shared action API'. >> >> >> > * all proposed APIs renamed according the above. >> >> >> > >> >> >> > The new shared action is an independent entity decoupled from any >> >> >> > flow >> >> >> > while any flow can reuse such an action. Please go over the RFC >> >> >> > description, it was almost entirely rewritten. >> >> >> > >> >> >> > @Jerin Jacob: >> >> >> > Thanks again for your comments, it made me admit that v1 description >> >> >> > was >> >> >> > incomplete & unclear. I hope v2 will be better at least in terms of >> >> >> > clarity. >> >> >> >> >> >> The public API and its usage is very clear. Thanks for this RFC. >> >> > >> >> > >> >> > My pleasure. >> >> >> >> >> >> >> >> >> I think, RFC v2 still not addressing the concern raised in the >> >> >> http://mails.dpdk.org/archives/dev/2020-June/169296.html. >> >> >> >> >> >> Since MLX hardware has an HW based shared object it is fine to have >> >> >> public API based on that level of abstraction. >> >> >> But at the PMD driver level we need to choose the correct abstraction >> >> >> to support all PMD and support shared object scheme if possible. >> >> >> >> >> >> I purpose to introduce something below or similar >> >> >> int (*action_update) >> >> >> (struct rte_eth_dev *, >> >> >> struct rte_flow *flow, >> >> >> const struct rte_flow_action [], >> >> >> struct rte_flow_error *); >> >> > >> >> > Where this callback suppose to belong (struct rte_flow_ops)? >> >> >> >> Yes. >> >> >> >> > How should it be implemented by PMD? >> >> >> >> See below, >> >> >> >> > Is it about shared action and if "yes" why there is 'flow' argument? >> >> >> >> flow holds the "pattern" and "action" data as PMD specific handle. >> >> So PMD, implementation can just change that action if it gets the PMD >> >> specific handle. >> >> >> >> >> >> >> >> >> >> >> >> >> in addition to: shared_action_create, shared_action_destroy, >> >> >> shared_action_update, shared_action_query >> >> >> >> >> >> Have generic implementation of above, if action_update callback is not >> >> >> NULL. >> >> > >> >> > "is not NULL" -> "is NULL"? >> >> >> >> Yes. When it is NULL. >> > >> > >> > Jerin, few clarifications regarding generic implementation of shared >> > action: >> > Based on this conversation I'm assuming that generic implementation >> > supposed to be something like: >> > For each flow using some shared action: >> > call ops-> action_update() >> > If the assumption above correct: >> > 1. taking into account that shared_action_update() is atomic, how can this >> > deal with partial success: some flows may fail validation - should it: >> > 1.1.lock all flows >> > 1.2.validate all flows >> > 1.3.update all flows >> > 1.4. unlock >> >> Yes. > > This kind of locking in addition to shared session management requires > locking of each flow_create/flow_destroy in addition to action_uodate > callback implementation even if there are no shared actions at all. In other > words it imposes an overhead on all PMDs that don't support shared action > natively.
Yes. That's what my concern with implementing shared session if the PMD only supports only action update for the given rte_flow *. Another approach would be to introduce rte_flow_action_update() public API which can either take "const struct rte_flow_action []" OR shared context ID, to cater to both cases or something on similar lines. >> >> >> > 2. action_update callback is PMD specific & if it's unsupported there is >> > no support for shared action any way >> >> Yes. >> >> > Please address the issues above >> >> > >> >> > >> >> >> >> >> >> So that, it can work all PMDs and to >> >> >> avoid the duplication of "complex" shared session management code. >> >> > >> >> > Do you mean shared action in use by multiple flows by "shared session"? >> >> >> >> Yes. >> > >> > Common 'shared session' management code: >> > - can be reduced to atomic usage counter >> > - maintaining list of flow using shared action expected to impact >> > performance & not necessary for all PMD specific implementations >> > Access to other shared resources hard to generalize because: >> > - for some PMDs mutual exclusion is HW feature & no need to protect it in >> > SW >> > - for others there may be multiple resources & access to each one >> > protected by different mechanism >> >> The general callback you can assume, it supports only action_update >> based callback. >> If PMD has mutual exclusion HW feature then it can override the >> function pointers. >> >> >> >> > An observation related to action_update callback: >> > If replaced (updated) action was shared then the flow won't be influenced >> > any more by updates or removed shared action.
