Fixes for NCCL_MAX_NCHANNELS and topo_expl (#398)

src/graph/connect.cc

@@ -292,6 +292,7 @@ ncclResult_t ncclTopoPostset(struct ncclComm* comm, int* firstRanks, int* treePa
 
   // Get number of channels after duplication
   nc *= comm->nChannels;
+  nc = std::min((int)ncclMaxNchannels(), nc);
   // Duplication should be complete now
   nChannels = comm->nChannels = std::min(MAXCHANNELS,nChannels*2);
 

tools/topo_expl/utils.cpp

@@ -404,7 +404,7 @@ ncclResult_t initTransportsRank_1(struct ncclComm* comm, struct allGather1Data_t
 
   if ((comm->topo->type & RCCL_TOPO_4P2H_ROME) && (comm->topo->type & RCCL_TOPO_GDR_ALL)) {
     if (rcclParamP2pNetDisable() == 0) {
-      STORE(comm->p2pNet, 1);
+      comm->p2pNet = 1;
       INFO(NCCL_INIT, "RCCL enabled same node P2P over network");
     }
     else