On Fri, Mar 13, 2015 at 11:34 AM, Ola Liljedahl <[email protected]> wrote: > When I think about IPC, it is message passing between different programs > (different processes, different address spaces, possibly even different > machines). IPC provides services like address resolution (some form of name > lookup), being able to respond to messages, a model for message typing (so > you can parse and understand messages from different senders). One of the > main use cases for IPC would be between the control plane (which does not > use ODP) and the data plane (which would be implemented using ODP). > > Synchronization between threads using the same address space can be done in > many way (e.g. by posting ODP buffers to queues). What kind of generic > helpers are needed here?
I agree with Ola here. The problem you have seems to only apply to linux-generic, on some real HW platforms it should be possible to "transfer" packets from one process to another trough globally visible queue ids, indistinctly from the two entities being different ODP applications or different threads of the same ODP application. I think we need to first define better the visibility scope of pools and queues for ODP in general and see how it applies to linux-generic in particular. If needed linux-generic should make the queue ids and buffer ids globally visible transparently, not necessarily with best performance, the ODP design should first and foremost be clear and linux-generic is a reference software implementation. As for IPC, as Ola said, it should be a service that provides a form of communication framework between different ODP "workers", with the possibility of being able to synchronize on different message types. ENEA has had an IPC framework for a long time that works this way and provides transparent, reliable, scalable IPC, not only between processes on the same system, but between different nodes in a network. The protocol is even open sourced and available for Linux distributions. I think at the very least ODP should incorporate some of the design aspects, like for example defining new event types to be used for IPC and define an IPC API for exchanging messages between the different ODP instances. /Ciprian > > -- Ola > > > On 13 March 2015 at 09:49, Maxim Uvarov <[email protected]> wrote: >> >> What was decision of supporting IPC for ODP? Should I update IPC patches >> on the latest ODP now? >> >> In the latest IPC patch as I remember IPC was done on pktio level: >> a) odp pool is shared between 2 processes with shared consumer/producer >> paths for odp_buffer_t descriptors. >> 2) producer process adds odp_buffer_t to producer path. >> 3) consumer process reads odp_buffer_t from producer path, and translates >> it to it's own odp_buffer_t. >> 4) After some work consumer thread puts odp_buffer_t to producer path. So >> that control of the packet is back to first process and first process can >> free this packet from the pool. >> >> I.e. in fact that exchange between processes is done with odp_buffer_t >> handlers and no packet body coping. That is mostly description of software >> path, i.e. linux-generic. >> >> I need ipc for things like snort (single threaded app) and I think that >> the same way can be used for virtualization. >> >> Best regards, >> Maxim. >> >> _______________________________________________ >> lng-odp mailing list >> [email protected] >> http://lists.linaro.org/mailman/listinfo/lng-odp > > > > _______________________________________________ > lng-odp mailing list > [email protected] > http://lists.linaro.org/mailman/listinfo/lng-odp > _______________________________________________ lng-odp mailing list [email protected] http://lists.linaro.org/mailman/listinfo/lng-odp
