On Tue, Dec 15, 2009 at 12:18 PM, Ira Weiny <wei...@llnl.gov> wrote: > On Tue, 15 Dec 2009 10:15:32 -0700 > Jason Gunthorpe <jguntho...@obsidianresearch.com> wrote: > >> > > However, I don't understand the comment "Only set HopLimit if going >> > > through a >> > > router"? >> > >> > This is from '#ifdef ROUTER_EXP' days - as far as I could understand >> > HopLimit should be set to IB_HOPLIMIT_MAX for inter-subnet MADs. >> >> If HopLimit is 0 then no GRH is required, if it is non 0 then the user >> of that path needs to apply a GRH. IIRC there are already a few things >> in the kernel that follow this? > > Is that in the spec somewhere?
IBA 1.2.1 vol 1 p.229 8.3.6 for one. > The follow on would be that if they specify a > DGID in the PathRecord query and the result is subnet local they must still > use a GRH even if the packet is going to stay local? No; with subnet local traffic, GRH is optional. -- Hal > I think this makes sense > but I wonder if __everyone__ is following that? > > Ira > >> >> Jason > > > -- > Ira Weiny > Math Programmer/Computer Scientist > Lawrence Livermore National Lab > 925-423-8008 > wei...@llnl.gov > -- To unsubscribe from this list: send the line "unsubscribe linux-rdma" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
