Hi Kefu, On Sat, Jan 5, 2019 at 6:42 AM kefu chai <tchaikov@xxxxxxxxx> wrote: > > as you might know, seastar encourage a share-nothing programming > paradigm. as in previous discussions we found that there are always > some cross-core communications in the sharded seastar-osd, because > there are couple infrastructures could be shared by a sharded OSD, > namely: > > - osdmap cache > - connection to peer OSDs, and heartbeats with them > - connection to monitor and mgr, and beacon/reports to them > - i/o to the underlying objectstore > > recently, when we are working on cross-core messenger[0], we found > that, in order to share the connection between cores we need to have > types like "seastar::lw_shared_ptr<seastar::foreign_ptr<ConnectionRef>>", > because > - the connections to peer OSDs are shared across cores, > - the connections are shared by multiple continuations on the local > core -- either locally or remotely. I'm not up-to-speed on all the proposals here but it seems to me the simple solution for the peer OSD connection is to have multiple connections between peer OSDs (one for each PG?). Is that not feasible for some reason? -- Patrick Donnelly
