> From: Jerin Jacob [mailto:jerin.ja...@caviumnetworks.com] > Sent: Friday, June 30, 2017 2:21 PM > To: Van Haaren, Harry <harry.van.haa...@intel.com> > Cc: Richardson, Bruce <bruce.richard...@intel.com>; dev@dpdk.org; > tho...@monjalon.net; > Wiles, Keith <keith.wi...@intel.com> > Subject: Re: Service lcores and Application lcores > > -----Original Message----- > > Date: Fri, 30 Jun 2017 13:08:26 +0000 > > From: "Van Haaren, Harry" <harry.van.haa...@intel.com> > > To: Jerin Jacob <jerin.ja...@caviumnetworks.com> > > CC: "Richardson, Bruce" <bruce.richard...@intel.com>, "dev@dpdk.org" > > <dev@dpdk.org>, "tho...@monjalon.net" <tho...@monjalon.net>, "Wiles, > > Keith" <keith.wi...@intel.com> > > Subject: RE: Service lcores and Application lcores > > > > > From: Jerin Jacob [mailto:jerin.ja...@caviumnetworks.com] > > > Sent: Friday, June 30, 2017 1:52 PM > > > To: Van Haaren, Harry <harry.van.haa...@intel.com> > > > Cc: Richardson, Bruce <bruce.richard...@intel.com>; dev@dpdk.org; > > > tho...@monjalon.net; > > > Wiles, Keith <keith.wi...@intel.com> > > > Subject: Re: Service lcores and Application lcores > > > > > > -----Original Message----- > > > > Date: Fri, 30 Jun 2017 10:00:18 +0000 > > > > From: "Van Haaren, Harry" <harry.van.haa...@intel.com> > > > > To: Jerin Jacob <jerin.ja...@caviumnetworks.com>, "Richardson, Bruce" > > > > <bruce.richard...@intel.com> > > > > CC: "dev@dpdk.org" <dev@dpdk.org>, "tho...@monjalon.net" > > > > <tho...@monjalon.net>, "Wiles, Keith" <keith.wi...@intel.com> > > > > Subject: RE: Service lcores and Application lcores > > > > <snip previous non-related items> > > > > > > I don't think providing a remote-launch API is actually beneficial. > > > > Remote-launching > a > > > single service > > > > is equivalent to adding that lcore as a service-core, and mapping it to > > > > just that > single > > > service. > > > > The advantage of adding it as a service core, is future-proofing for if > > > > more > services > > > need to be added > > > > to that core in future, and statistics of the service core > > > > infrastructure. A > convenience > > > API could be > > > > provided to perform the core_add(), service_start(), > > > > enable_on_service() and > > > core_start() APIs in one. > > > > > > > > Also, the remote_launch API doesn't solve the original problem - what > > > > if an > application > > > lcore wishes > > > > to run one iteration of a service "manually". The remote_launch style > > > > API does not > solve > > > this problem. > > > > > > Agree with problem statement. But, remote_launch() operates on lcores not > > > on > > > not necessary on 1:1 mapped physical cores. > > > > > > By introducing "rte_service_iterate", We are creating a parallel > > > infrastructure to > > > run the service on non DPDK service lcores aka normal lcores. > > > Is this really required? Is there any real advantage for > > > application not use builtin service lcore infrastructure, rather than > > > iterating over > > > "rte_service_iterate" and run on normal lcores. If we really want to mux > > > a physical core to N lcore, EAL already provides that in the form of > > > threads. > > > > > > I think, providing too many parallel options for the same use case may be > > > a overkill. > > > > > > Just my 2c. > > > > > > The use-case that the rte_service_iterate() caters for is one where the > > application > > wishes to run a service on an "ordinary app lcore", together with an > > application > workload. > > > > For example, the eventdev-scheduler and one worker can be run on the same > > lcore. If the > schedule() running thread *must* be a service lcore, we would not be able to > also use that > lcore as an application worker core. > > > > That was my motivation for adding this API, I do agree with you above; it > > is a second > "parallel" method to run a service. I think there's enough value in enabling > the use-case > as per example above to add it. > > > > > > Do you see enough value in the use-case above to add the API? > > The above use case can be realized like --lcores='(0-1)@1'(Two lcore on > an physical core). I believe, application writers never want to write a > code based on specific number of cores available in the system. If they > do then they will be stuck on running on another environment and too > many combination to address.
Good point. > For me it complicates service lcore usage. But someone think, it will useful > then > I don't have strong objection. We can easily add APIs later - and removing them isn't so easy. +1 from me leave it out for now, and we can see about adding it for 17.11 if the need arises. Thanks for your input, I'll spin a v3 without the rte_service_iterate() function, and that should be it then!
