Add another Rome model (#553)

* Add another Rome model

* Add option to force enable intranet on single node

* Limit p2p channels to number of ranks

* Refine p2p channels handling

[ROCm/rccl commit: ef499c4810]

projects/rccl/src/graph/paths.cc

@@ -576,6 +576,8 @@ ncclResult_t ncclTopoComputePaths(struct ncclTopoSystem* system, struct ncclPeer
   return ncclSuccess;
 }
 
+RCCL_PARAM(EnableIntranet, "ENABLE_INTRANET", 0);
+
 ncclResult_t ncclTopoTrimSystem(struct ncclTopoSystem* system, struct ncclComm* comm) {
   int *domains;
   int64_t *ids;
@@ -669,6 +671,10 @@ ncclResult_t ncclTopoTrimSystem(struct ncclTopoSystem* system, struct ncclComm*
       }
     }
   }
+  if (rcclParamEnableIntranet()) {
+    remove = 0;
+    system->type |= RCCL_TOPO_FORCE_INTRA;
+  }
   comm->localRanks = system->nodes[GPU].count;
   if (system->nodes[GPU].count == comm->nRanks && remove) {
     for (int n=system->nodes[NET].count-1; n>=0; n--)
@@ -741,7 +747,7 @@ ncclResult_t ncclTopoComputeP2pChannels(struct ncclComm* comm) {
   else {
     // Round to next pow2 nChannelsPerPeer and nChannels
     comm->p2pnChannelsPerPeer = nextPow2(minChannels);
-    comm->p2pnChannels = nextPow2(comm->p2pnChannels);
+    comm->p2pnChannels = std::min(comm->topo->nodes[GPU].count == comm->topo->nRanks ? 2*comm->nRanks : comm->nRanks, nextPow2(comm->p2pnChannels));
   }
 
   // Init channels that weren't used so far