diff --git a/include/nccl_ofi_rdma.h b/include/nccl_ofi_rdma.h
index d7b468352..a57e14c8d 100644
--- a/include/nccl_ofi_rdma.h
+++ b/include/nccl_ofi_rdma.h
@@ -517,6 +517,9 @@ struct nccl_net_ofi_ep_rail {
 	/* Completion Queue handle */
 	struct fid_cq *cq;
 
+	/* Access domain handles */
+	struct fid_domain *domain;
+
 	/*
 	 * Bounce buffer management
 	 */
diff --git a/include/nccl_ofi_sendrecv.h b/include/nccl_ofi_sendrecv.h
index a2cd2403d..d2366f15b 100644
--- a/include/nccl_ofi_sendrecv.h
+++ b/include/nccl_ofi_sendrecv.h
@@ -110,6 +110,9 @@ typedef struct nccl_net_ofi_sendrecv_ep {
 	/* Endpoint handle to communicate to */
 	struct fid_ep *ofi_ep;
 
+	/* Access Domain handle */
+	struct fid_domain *domain;
+
 	/* Address vector handle */
 	struct fid_av *av;
 
diff --git a/src/nccl_ofi_rdma.c b/src/nccl_ofi_rdma.c
index 33f84bc98..ab4127c6c 100644
--- a/src/nccl_ofi_rdma.c
+++ b/src/nccl_ofi_rdma.c
@@ -249,6 +249,15 @@ static inline nccl_net_ofi_ep_rail_t *get_rail(nccl_net_ofi_rdma_ep_t *ep,
 	return &ep->rails[rail_id];
 }
 
+/*
+ * @brief return the domain for the endpoint and rail.
+ */
+
+static inline struct fid_domain *get_domain_from_endpoint(nccl_net_ofi_rdma_ep_t *ep, int rail_id)
+{
+	return get_rail(ep, rail_id)->domain;
+}
+
 /*
  * @brief	Unlink temporary NCCL topology file written by `write_topo_file()`
  *
@@ -2428,6 +2437,7 @@ static int reg_mr_ep(nccl_net_ofi_rdma_ep_t *ep, void *data,
 	struct fi_mr_attr mr_attr = {0};
 	struct iovec iov = {0};
 	nccl_net_ofi_rdma_mr_handle_t *ret_handle = NULL;
+	struct fid_domain *domain;
 	*mhandle = NULL;
 
 	assert(ep);
@@ -2461,10 +2471,10 @@ static int reg_mr_ep(nccl_net_ofi_rdma_ep_t *ep, void *data,
 	/* Register memory on each rail */
 	ret_handle->num_rails = num_rails;
 	for (int rail_id = 0; rail_id != num_rails; ++rail_id) {
-		nccl_net_ofi_rdma_device_rail_t *dev_rail = get_device_rail(device, rail_id);
 		nccl_net_ofi_ep_rail_t *rail = get_rail(ep, rail_id);
+		domain = get_domain_from_endpoint(ep, rail_id);
 
-		ret = register_rail_mr_buffer(dev_rail->domain, rail->ofi_ep,
+		ret = register_rail_mr_buffer(domain, rail->ofi_ep,
 					      dev_id, type, &mr_attr,
 					      &ret_handle->mr[rail_id]);
 		if (OFI_UNLIKELY(ret != 0)) {
@@ -5312,7 +5322,19 @@ static int ep_rail_init(nccl_net_ofi_rdma_ep_t *ep,
 {
 	int ret = 0;
 
-	ret = nccl_ofi_ofiutils_init_connection(FI_VERSION(1, 18), dev_rail->info, dev_rail->domain, &ep_rail->ofi_ep,
+	if (domain_per_thread == 1) {
+		ret = fi_domain(dev_rail->fabric, dev_rail->info,
+			&ep_rail->domain, NULL);
+		if (OFI_UNLIKELY(ret != 0)) {
+			NCCL_OFI_WARN("Couldn't open a fabric access domain. RC: %d, ERROR: %s",
+				ret, fi_strerror(-ret));
+			return ret;
+		}
+	} else {
+		ep_rail->domain = dev_rail->domain;
+	}
+
+	ret = nccl_ofi_ofiutils_init_connection(FI_VERSION(1, 18), dev_rail->info, ep_rail->domain, &ep_rail->ofi_ep,
 						&ep_rail->av, &ep_rail->cq);
 	if (ret != 0) {
 		return ret;
@@ -5582,13 +5604,21 @@ static int init_device_rail_ofi_resources(nccl_net_ofi_rdma_device_rail_t *rail_
 		goto error;
 	}
 
-	/* Create domain */
-	ret = fi_domain(rail_dev->fabric, rail_dev->info,
-			&rail_dev->domain, NULL);
-	if (OFI_UNLIKELY(ret != 0)) {
-		NCCL_OFI_WARN("Couldn't open a fabric access domain. RC: %d, ERROR: %s",
-			      ret, fi_strerror(-ret));
-		goto error;
+	/*
+         * In the domain-per-thread case, create the domain in the endpoint structure.  In the
+         * domain-per-process case, keep it in the device structure.  This is because, on some
+         * platforms, libfabric locks when accessing the domain, so retaining separate domains
+         * per thread and per endpoint reduces contention for that lock.
+         */
+	if (domain_per_thread == 0) {
+		/* Create domain */
+		ret = fi_domain(rail_dev->fabric, rail_dev->info,
+				&rail_dev->domain, NULL);
+		if (OFI_UNLIKELY(ret != 0)) {
+			NCCL_OFI_WARN("Couldn't open a fabric access domain. RC: %d, ERROR: %s",
+				      ret, fi_strerror(-ret));
+			goto error;
+		}
 	}
 
 	return ret;
diff --git a/src/nccl_ofi_sendrecv.c b/src/nccl_ofi_sendrecv.c
index a6d7e4251..3f4e2649f 100644
--- a/src/nccl_ofi_sendrecv.c
+++ b/src/nccl_ofi_sendrecv.c
@@ -469,6 +469,19 @@ static int post_recv_conn(nccl_net_ofi_sendrecv_listen_comm_t *l_comm,
 	return rc;
 }
 
+/*
+ * @brief	Returns the domain, dependent on the platform.
+ *
+ * @return	fid_domain for the device (P-series) or endpoint (Neuron).
+ *
+ */
+
+static inline struct fid_domain* get_domain_from_endpoint(nccl_net_ofi_sendrecv_ep_t *ep)
+{
+	return ep->domain;
+}
+
+
 /*
  * @brief	Registers memory region (both HOST and CUDA)
  *
@@ -687,7 +700,9 @@ static int reg_mr_base_comm(nccl_net_ofi_comm_t *base_comm, void *data,
 	int dev_id = device->base.dev_id;
 
 	nccl_ofi_idpool_t *key_pool = &device->key_pool;
-	return reg_mr_base(device->domain, ep->ofi_ep, key_pool,
+	struct fid_domain *domain;
+	domain = get_domain_from_endpoint(ep);
+	return reg_mr_base(domain, ep->ofi_ep, key_pool,
 			   dev_id, data, size, type, mhandle);
 }
 
@@ -1169,6 +1184,7 @@ static nccl_net_ofi_sendrecv_recv_comm_t *prepare_recv_comm(nccl_net_ofi_sendrec
 {
 	int ret = 0;
 	fi_addr_t remote_ep;
+	struct fid_domain *domain;
 	nccl_net_ofi_sendrecv_recv_comm_t *r_comm = NULL;
 	size_t req_size = sizeof(nccl_net_ofi_sendrecv_req_t);
 	nccl_ofi_idpool_t *key_pool = &device->key_pool;
@@ -1216,13 +1232,15 @@ static nccl_net_ofi_sendrecv_recv_comm_t *prepare_recv_comm(nccl_net_ofi_sendrec
 		return NULL;
 	}
 
+	domain = get_domain_from_endpoint(ep);
+
 	/*
 	 * Setup flush resources if using GPUDirect RDMA unless user disables
 	 * flush operations
 	 */
 	if (!ofi_nccl_gdr_flush_disable() && support_gdr == GDR_SUPPORTED && !cuda_flush) {
 		r_comm->flush_buff.size = NCCL_OFI_FLUSH_SIZE;
-		ret = alloc_and_reg_flush_buff(device->domain, ep->ofi_ep, key_pool,
+		ret = alloc_and_reg_flush_buff(domain, ep->ofi_ep, key_pool,
 					       &r_comm->flush_buff, dev_id);
 		if (OFI_UNLIKELY(ret != 0)) {
 			free(r_comm);
@@ -2084,6 +2102,18 @@ static int get_ep(nccl_net_ofi_device_t *base_dev,
 				       "Unable to allocate sendrecv endpoint");
 			goto unlock;
 		}
+		if (domain_per_thread == 1) {
+			ret = fi_domain(device->fabric, device->info,
+				&ep->domain, NULL);
+			if (OFI_UNLIKELY(ret != 0)) {
+				NCCL_OFI_WARN("Couldn't open a fabric access domain. RC: %d, ERROR: %s",
+					ret, fi_strerror(-ret));
+				free(ep);
+				goto unlock;
+			}
+		} else {
+			ep->domain = device->domain;
+		}
 
 		/* Initialize base endpoint */
 		ep->base.device = &device->base;
@@ -2107,7 +2137,9 @@ static int get_ep(nccl_net_ofi_device_t *base_dev,
 	}
 
 	if (ep->ref_cnt == 0) {
-		ret = nccl_ofi_ofiutils_init_connection(selected_api_version, device->info, device->domain, &ep->ofi_ep,
+		struct fid_domain *domain;
+		domain = get_domain_from_endpoint(ep);
+		ret = nccl_ofi_ofiutils_init_connection(selected_api_version, device->info, domain, &ep->ofi_ep,
 							&ep->av, &ep->cq);
 		if (ret != 0) {
 			goto unlock;
@@ -2160,13 +2192,21 @@ static int device_prepare_for_connection(nccl_net_ofi_sendrecv_device_t *device)
 		goto error;
 	}
 
-	/* Create domain */
-	ret = fi_domain(device->fabric, device->info,
-			&device->domain, NULL);
-	if (OFI_UNLIKELY(ret != 0)) {
-		NCCL_OFI_WARN("Couldn't open a fabric access domain. RC: %d, ERROR: %s",
-			      ret, fi_strerror(-ret));
-		goto error;
+	/*
+	 * In the domain-per-thread case, create the domain in the endpoint structure.  In the
+	 * domain-per-process case, keep it in the device structure.  This is because, on some
+	 * platforms, libfabric locks when accessing the domain, so retaining separate domains
+	 * per thread and per endpoint reduces contention for that lock.
+	 */
+	if (domain_per_thread == 0) {
+		/* Create domain */
+		ret = fi_domain(device->fabric, device->info,
+				&device->domain, NULL);
+		if (OFI_UNLIKELY(ret != 0)) {
+			NCCL_OFI_WARN("Couldn't open a fabric access domain. RC: %d, ERROR: %s",
+				      ret, fi_strerror(-ret));
+			goto error;
+		}
 	}
 
 	return ret;
diff --git a/src/platform-aws.c b/src/platform-aws.c
index 3999d3049..fd056d3ea 100644
--- a/src/platform-aws.c
+++ b/src/platform-aws.c
@@ -543,6 +543,7 @@ int platform_init(const char **provider_filter)
 	if (domain_per_thread == -1) {
 		domain_per_thread = platform_data->domain_per_thread;
 	}
+	NCCL_OFI_INFO(NCCL_INIT | NCCL_NET, "Creating one domain per %s", domain_per_thread ? "process" : "thread");
 
 exit:
 	return ret;