Merge remote-tracking branch 'ncclRepo/master' into develop

src/include/channel.h

@@ -10,5 +10,36 @@
 
 ncclResult_t initChannel(struct ncclComm* comm, int channelid);
 ncclResult_t freeChannel(struct ncclChannel* channel, int nRanks);
+static ncclResult_t ncclChannelComputeBase(struct ncclComm* comm, int peer, int coll, int*channelBase) {
+  int p2pGroupSize = NCCL_MAX_WORK_ELEMENTS_P2P/2;
+  int peerNode = comm->rankToNode[peer];
+  int peerIndex = comm->rankToLocalRank[peer];
+  int nsteps = comm->maxLocalRanks;
+  int rankIndex = comm->rankToLocalRank[comm->rank];
+  int step, delta;
+  if (coll == ncclFuncSend) {
+    step = (nsteps + peerIndex - rankIndex)%nsteps;
+    delta = (comm->nNodes + peerNode - comm->node) % comm->nNodes;
+  } else if (coll == ncclFuncRecv) {
+    step = (nsteps + rankIndex - peerIndex)%nsteps;
+    delta = (comm->nNodes + comm->node - peerNode) % comm->nNodes;
+  } else {
+    return ncclInternalError;
+  }
+  *channelBase = comm->nNodes > 1 ? delta+(step/p2pGroupSize) : step;
+  return ncclSuccess;
+}
+
+static ncclResult_t ncclChannelComputeFromBase(struct ncclComm* comm, int base, int channelInc, int*channelId) {
+  *channelId = (base+comm->p2pChannels[channelInc]) % comm->p2pnChannels;
+  return ncclSuccess;
+}
+
+static ncclResult_t ncclChannelCompute(struct ncclComm* comm, int peer, int channelInc, int coll, int*channelId) {
+  int base;
+  NCCLCHECK(ncclChannelComputeBase(comm, peer, coll, &base));
+  NCCLCHECK(ncclChannelComputeFromBase(comm, base, channelInc, channelId));
+  return ncclSuccess;
+}
 
 #endif