On Mon, 2007-11-12 at 22:21 +0200, Sasha Khapyorsky wrote: > Hi, > > On 19:13 Mon 12 Nov , Bernd Schubert wrote: > > > > so far we always did run opensm without the --lmc option, but just recently > > I > > read in opensm's manpage about it. > > > > <opensm manpage> > > This option specifies the subnet's LMC value. The number of LIDs assigned > > to > > each port is 2^LMC. > > The LMC value must be in the range 0-7. LMC values > 0 allow multiple > > paths > > between ports. LMC values > 0 should only be used if the subnet topology > > actually provides multiple paths between ports, i.e. multiple > > interconnects between switches. Without -l, OpenSM defaults to LMC = 0, > > which allows one path between any two ports. > > </opensm manpage> > > > > In one of our configurations we do have a mts2400 (master) switch and > > connected to it are two mts14400 switches (each with 3 connections to the > > the > > mts2400). > > I think from the description of the opensm manpage we need to give the > > "--lmc" > > to make use of the 3 connections from each mts14400 switch to the mts2400 > > switch, don't we? > > In theory (AFAIR by default OpenSM will not assign LMC for Switch port 0
Non 0 LMC is only valid (per spec) for enhanced SP0. LMC must be 0 for base SP0. > due to some chip bug), when target is switch itself. But if you have > end nodes connected to this switch and targets are end nodes when OpenSM > will try to use all links for it. > > > Furthermore, from manpage I would think we even need this > > option for proper inter-communication between the switch modules? > > For switch modules yes, but again OpenSM will not assign LMC for > switches (even then --lmc specified), only for end nodes. In order to > enable it you will need to turn on 'lmc_esp0' option in OpenSM options > file. But as far as I remember it is not supported by switches now. It didn't work last time I tried it and I don't think it's been fixed. -- Hal > Sasha > _______________________________________________ > general mailing list > [email protected] > http://lists.openfabrics.org/cgi-bin/mailman/listinfo/general > > To unsubscribe, please visit http://openib.org/mailman/listinfo/openib-general _______________________________________________ general mailing list [email protected] http://lists.openfabrics.org/cgi-bin/mailman/listinfo/general To unsubscribe, please visit http://openib.org/mailman/listinfo/openib-general
