> From: Thomas Monjalon [mailto:tho...@monjalon.net] > Sent: Wednesday, March 28, 2018 8:30 AM > To: Tan, Jianfeng <jianfeng....@intel.com> > Cc: Burakov, Anatoly <anatoly.bura...@intel.com>; dev@dpdk.org; Ananyev, > Konstantin <konstantin.anan...@intel.com>; Van Haaren, Harry > <harry.van.haa...@intel.com> > Subject: Re: [dpdk-dev] [PATCH v6 2/2] eal: add asynchronous request API to > DPDK IPC > > 28/03/2018 04:08, Tan, Jianfeng: > > Hi Thomas , > > > > From: Thomas Monjalon [mailto:tho...@monjalon.net] > > > 27/03/2018 15:59, Anatoly Burakov: > > > > Under the hood, we create a separate thread to deal with replies to > > > > asynchronous requests, that will just wait to be notified by the > > > > main thread, or woken up on a timer. > > > > > > I really don't like that a library is creating a thread. > > > We don't even know where the thread is created (which core). > > > Can it be a rte_service? or in the interrupt thread? > > > > Agree that we'd better not adding so many threads in a library. > > > > I was considering to merge all the threads into the interrupt thread, > however, we don't have an interrupt thread in freebsd. Further, we don't > implement alarm API in freebsd. That's why I tend to current implementation, > and optimize it later. > > I would prefer we improve the current code now instead of polluting more > with more uncontrolled threads. > > > For rte_service, it may be not a good idea to reply on it as it needs > explicit API calls to setup. > > I don't see the issue of the explicit API. > The IPC is a new service.
Although I do like to see new services, if we want to enable "core" dpdk functionality with Services, we need a proper designed solution for that. Service cores is not intended for "occasional" work - there is no method to block and sleep on a specific service until work becomes available, so this would imply a busy-polling. Using a service (hence busy polling) for rte_malloc()-based memory mapping requests is inefficient, and total overkill :) For this patch I suggest to use some blocking-read capable mechanism. The above said, in the longer term it would be good to have a design that allows new file-descriptors to be added to a "dpdk core" thread, which performs occasional lengthy work if the FD has data available.
