nvmf/rdma: Add RDMA polling statistics

RDMA polling statistics: number of polls and number of completion
entries returned.

Signed-off-by: Evgeniy Kochetov <evgeniik@mellanox.com>
Change-Id: Iabcf2cb6f6a35f595b89b58cdfcd177a637dda13
Reviewed-on: https://review.gerrithub.io/c/spdk/spdk/+/445289
Tested-by: SPDK CI Jenkins <sys_sgci@intel.com>
Reviewed-by: Jim Harris <james.r.harris@intel.com>
Reviewed-by: Ben Walker <benjamin.walker@intel.com>

doc/jsonrpc.md

@@ -4176,7 +4176,19 @@ Example response:
         "pending_bdev_io": 1721,
         "transports": [
           {
-            "trtype": "RDMA"
+            "trtype": "RDMA",
+            "devices": [
+              {
+                "name": "mlx5_1",
+                "polls": 1536729,
+                "completions": 0
+              },
+              {
+                "name": "mlx5_0",
+                "polls": 1536729,
+                "completions": 18667357
+              }
+            ]
           }
         ]
       }

include/spdk/nvmf.h

@@ -85,11 +85,18 @@ struct spdk_nvmf_poll_group_stat {
 	uint64_t pending_bdev_io;
 };
 
+struct spdk_nvmf_rdma_device_stat {
+	const char *name;
+	uint64_t polls;
+	uint64_t completions;
+};
+
 struct spdk_nvmf_transport_poll_group_stat {
 	spdk_nvme_transport_type_t trtype;
 	union {
 		struct {
-			int dummy;
+			uint64_t num_devices;
+			struct spdk_nvmf_rdma_device_stat *devices;
 		} rdma;
 	};
 };

lib/event/subsystems/nvmf/nvmf_rpc.c

@@ -1612,11 +1612,23 @@ static void
 write_nvmf_transport_stats(struct spdk_json_write_ctx *w,
 			   struct spdk_nvmf_transport_poll_group_stat *stat)
 {
+	uint64_t i;
+
 	spdk_json_write_object_begin(w);
 	spdk_json_write_named_string(w, "trtype",
 				     spdk_nvme_transport_id_trtype_str(stat->trtype));
 	switch (stat->trtype) {
 	case SPDK_NVME_TRANSPORT_RDMA:
+		spdk_json_write_named_array_begin(w, "devices");
+		for (i = 0; i < stat->rdma.num_devices; ++i) {
+			spdk_json_write_object_begin(w);
+			spdk_json_write_named_string(w, "name", stat->rdma.devices[i].name);
+			spdk_json_write_named_uint64(w, "polls", stat->rdma.devices[i].polls);
+			spdk_json_write_named_uint64(w, "completions", stat->rdma.devices[i].completions);
+			spdk_json_write_object_end(w);
+		}
+		spdk_json_write_array_end(w);
+		break;
 	default:
 		break;
 	}

lib/nvmf/rdma.c

@@ -409,6 +409,11 @@ struct spdk_nvmf_rdma_qpair {
 	bool					last_wqe_reached;
 };
 
+struct spdk_nvmf_rdma_poller_stat {
+	uint64_t				completions;
+	uint64_t				polls;
+};
+
 struct spdk_nvmf_rdma_poller {
 	struct spdk_nvmf_rdma_device		*device;
 	struct spdk_nvmf_rdma_poll_group	*group;
@@ -424,6 +429,7 @@ struct spdk_nvmf_rdma_poller {
 	struct ibv_srq				*srq;
 
 	struct spdk_nvmf_rdma_resources		*resources;
+	struct spdk_nvmf_rdma_poller_stat	stat;
 
 	TAILQ_HEAD(, spdk_nvmf_rdma_qpair)	qpairs;
 
@@ -3420,6 +3426,9 @@ spdk_nvmf_rdma_poller_poll(struct spdk_nvmf_rdma_transport *rtransport,
 		return -1;
 	}
 
+	rpoller->stat.polls++;
+	rpoller->stat.completions += reaped;
+
 	for (i = 0; i < reaped; i++) {
 
 		rdma_wr = (struct spdk_nvmf_rdma_wr *)wc[i].wr_id;
@@ -3654,6 +3663,10 @@ spdk_nvmf_rdma_poll_group_get_stat(struct spdk_nvmf_tgt *tgt,
 	struct spdk_io_channel *ch;
 	struct spdk_nvmf_poll_group *group;
 	struct spdk_nvmf_transport_poll_group *tgroup;
+	struct spdk_nvmf_rdma_poll_group *rgroup;
+	struct spdk_nvmf_rdma_poller *rpoller;
+	struct spdk_nvmf_rdma_device_stat *device_stat;
+	uint64_t num_devices = 0;
 
 	if (tgt == NULL || stat == NULL) {
 		return -EINVAL;
@@ -3669,6 +3682,27 @@ spdk_nvmf_rdma_poll_group_get_stat(struct spdk_nvmf_tgt *tgt,
 				return -ENOMEM;
 			}
 			(*stat)->trtype = SPDK_NVME_TRANSPORT_RDMA;
+
+			rgroup = SPDK_CONTAINEROF(tgroup, struct spdk_nvmf_rdma_poll_group, group);
+			/* Count devices to allocate enough memory */
+			TAILQ_FOREACH(rpoller, &rgroup->pollers, link) {
+				++num_devices;
+			}
+			(*stat)->rdma.devices = calloc(num_devices, sizeof(struct spdk_nvmf_rdma_device_stat));
+			if (!(*stat)->rdma.devices) {
+				SPDK_ERRLOG("Failed to allocate NVMf RDMA devices statistics\n");
+				free(*stat);
+				return -ENOMEM;
+			}
+
+			(*stat)->rdma.num_devices = num_devices;
+			num_devices = 0;
+			TAILQ_FOREACH(rpoller, &rgroup->pollers, link) {
+				device_stat = &(*stat)->rdma.devices[num_devices++];
+				device_stat->name = ibv_get_device_name(rpoller->device->context->device);
+				device_stat->polls = rpoller->stat.polls;
+				device_stat->completions = rpoller->stat.completions;
+			}
 			return 0;
 		}
 	}
@@ -3678,6 +3712,9 @@ spdk_nvmf_rdma_poll_group_get_stat(struct spdk_nvmf_tgt *tgt,
 static void
 spdk_nvmf_rdma_poll_group_free_stat(struct spdk_nvmf_transport_poll_group_stat *stat)
 {
+	if (stat) {
+		free(stat->rdma.devices);
+	}
 	free(stat);
 }