1 files changed, 30 insertions, 23 deletions

diff --git a/src/include/net.h b/src/include/net.h
index 3d37c8c..bc81965 100644
--- a/src/include/net.h
+++ b/src/include/net.h
@@ -16,7 +16,7 @@ typedef char ncclNetHandle_t[NCCL_NET_HANDLE_MAXSIZE];
 // Translation to external API
 static const char* ncclNetName() { return ncclNet->name; }
 static ncclResult_t ncclNetDevices(int* ndev) { NCCLCHECK(ncclNet->devices(ndev)); return ncclSuccess; }
-static ncclResult_t ncclNetPciPath(int dev, char** path) { NCCLCHECK(ncclNet->pciPath(dev, path)); return ncclSuccess; }
+static ncclResult_t ncclNetGetProperties(int dev, ncclNetProperties_t* props) { NCCLCHECK(ncclNet->getProperties(dev, props)); return ncclSuccess; }
 static ncclResult_t ncclNetListen(int dev, void* handle, void** listenComm) { NCCLCHECK(ncclNet->listen(dev, handle, listenComm)); return ncclSuccess; }
 static ncclResult_t ncclNetConnect(int dev, void* handle, void** sendComm) { NCCLCHECK(ncclNet->connect(dev, handle, sendComm)); return ncclSuccess; }
 static ncclResult_t ncclNetAccept(void* listenComm, void** recvComm) { NCCLCHECK(ncclNet->accept(listenComm, recvComm)); return ncclSuccess; }
@@ -30,33 +30,40 @@ static ncclResult_t ncclNetCloseSend(void* sendComm) { NCCLCHECK(ncclNet->closeS
 static ncclResult_t ncclNetCloseRecv(void* recvComm) { NCCLCHECK(ncclNet->closeRecv(recvComm)); return ncclSuccess; }
 static ncclResult_t ncclNetCloseListen(void* listenComm) { NCCLCHECK(ncclNet->closeListen(listenComm)); return ncclSuccess; }
 
+// Test whether the current GPU support GPU Direct RDMA.
 #define GPU_BUF_SIZE (2*1024*1024)
-static ncclResult_t ncclNetPtrSupport(int dev, int* supportedTypes) {
-  int support;
-  NCCLCHECK(ncclNet->ptrSupport(dev, &support));
-  *supportedTypes = support & ~NCCL_PTR_CUDA;
-  // The network supports GPU Direct RDMA ; verify the GPU supports it as well.
-  if (support & NCCL_PTR_CUDA) {
+static ncclResult_t ncclGpuGdrSupport(int* gdrSupport) {
+  int netDevs;
+  NCCLCHECK(ncclNetDevices(&netDevs));
+  *gdrSupport = 0;
+  for (int dev=0; dev<netDevs; dev++) {
+    // Find a net device which is GDR-capable
+    ncclNetProperties_t props;
+    NCCLCHECK(ncclNet->getProperties(dev, &props));
+    if ((props.ptrSupport & NCCL_PTR_CUDA) == 0) continue;
+
+    // Allocate memory on the GPU and try to register it on the NIC.
     void *lComm = NULL, *sComm = NULL, *rComm = NULL;
     ncclNetHandle_t handle;
     void* gpuPtr = NULL;
     void* mHandle = NULL;
-    ncclResult_t res;
-    NCCLCHECKGOTO(ncclNetListen(dev, &handle, &lComm), res, cleanup);
-    NCCLCHECKGOTO(ncclNetConnect(dev, &handle, &sComm), res, cleanup);
-    NCCLCHECKGOTO(ncclNetAccept(lComm, &rComm), res, cleanup);
-    CUDACHECKGOTO(cudaMalloc(&gpuPtr, GPU_BUF_SIZE), res, cleanup);
-    NOWARN(ncclNetRegMr(sComm, gpuPtr, GPU_BUF_SIZE, NCCL_PTR_CUDA, &mHandle), res);
-    if (res != ncclSuccess) goto cleanup;
-    NCCLCHECKGOTO(ncclNetDeregMr(sComm, mHandle), res, cleanup);
-    NCCLCHECKGOTO(ncclNetRegMr(rComm, gpuPtr, GPU_BUF_SIZE, NCCL_PTR_CUDA, &mHandle), res, cleanup);
-    NCCLCHECKGOTO(ncclNetDeregMr(rComm, mHandle), res, cleanup);
-    *supportedTypes |= NCCL_PTR_CUDA;
-cleanup:
-    if (gpuPtr) cudaFree(gpuPtr);
-    if (rComm) ncclNetCloseRecv(rComm);
-    if (sComm) ncclNetCloseSend(sComm);
-    if (lComm) ncclNetCloseListen(lComm);
+    NCCLCHECK(ncclNetListen(dev, &handle, &lComm));
+    NCCLCHECK(ncclNetConnect(dev, &handle, &sComm));
+    NCCLCHECK(ncclNetAccept(lComm, &rComm));
+    CUDACHECK(cudaMalloc(&gpuPtr, GPU_BUF_SIZE));
+    ncclDebugNoWarn = NCCL_NET;
+    if (ncclNetRegMr(sComm, gpuPtr, GPU_BUF_SIZE, NCCL_PTR_CUDA, &mHandle) == ncclSuccess) {
+      NCCLCHECK(ncclNetDeregMr(sComm, mHandle));
+      NCCLCHECK(ncclNetRegMr(rComm, gpuPtr, GPU_BUF_SIZE, NCCL_PTR_CUDA, &mHandle));
+      NCCLCHECK(ncclNetDeregMr(rComm, mHandle));
+      *gdrSupport = 1;
+    }
+    ncclDebugNoWarn = 0;
+    CUDACHECK(cudaFree(gpuPtr));
+    NCCLCHECK(ncclNetCloseRecv(rComm));
+    NCCLCHECK(ncclNetCloseSend(sComm));
+    NCCLCHECK(ncclNetCloseListen(lComm));
+    break;
   }
   return ncclSuccess;
 }