rpc: Add nvmf_get_stats RPC method

This patch adds nvmf_get_stats RPC method and basic infrastructure to
report NVMf global and per poll group statistics in JSON format.

Signed-off-by: Evgeniy Kochetov <evgeniik@mellanox.com>
Change-Id: I13b83e28b75a02bc1dcb7b95cbce52ae10ff0f7b
Reviewed-on: https://review.gerrithub.io/c/spdk/spdk/+/452298
Tested-by: SPDK CI Jenkins <sys_sgci@intel.com>
Reviewed-by: Ben Walker <benjamin.walker@intel.com>
Reviewed-by: Shuhei Matsumoto <shuhei.matsumoto.xt@hitachi.com>
Reviewed-by: Darek Stojaczyk <dariusz.stojaczyk@intel.com>

CHANGELOG.md

@@ -30,6 +30,8 @@ poll group for the qpair. And `ConnectionScheduler` configuration is added into
 [Nvmf] section in etc/spdk/nvmf.conf.in to demonstrate how to configure the connection
 scheduling strategy among different spdk threads.
 
+Added infrastructure to retrieve global and per poll group NVMf statistics.
+
 ### notify
 
 The function `spdk_notify_get_types()` and `spdk_notify_get_events()` were
@@ -99,6 +101,8 @@ spdk_sock_group_create() is updated to allow input the user provided ctx.
 
 Added thread_get_stats RPC method to retrieve existing statistics.
 
+Added nvmf_get_stats RPC method to retrieve NVMf susbsystem statistics.
+
 ## v19.04:
 
 ### nvme

doc/jsonrpc.md

@@ -4138,6 +4138,44 @@ Example response:
 }
 ~~~
 
+## nvmf_get_stats method {#rpc_nvmf_get_stats}
+
+Retrieve current statistics of the NVMf subsystem.
+
+### Parameters
+
+This method has no parameters.
+
+### Response
+
+The response is an object containing NVMf subsystem statistics.
+
+### Example
+
+Example request:
+~~~
+{
+  "jsonrpc": "2.0",
+  "method": "nvmf_get_stats",
+  "id": 1
+}
+~~~
+
+Example response:
+~~~
+{
+  "jsonrpc": "2.0",
+  "id": 1,
+  "result": {
+    "poll_groups": [
+      {
+        "name": "app_thread"
+      }
+    ]
+  }
+}
+~~~
+
 # Vhost Target {#jsonrpc_components_vhost_tgt}
 
 The following common preconditions need to be met in all target types.

include/spdk/nvmf.h

@@ -2,7 +2,7 @@
  *   BSD LICENSE
  *
  *   Copyright (c) Intel Corporation. All rights reserved.
- *   Copyright (c) 2018 Mellanox Technologies LTD. All rights reserved.
+ *   Copyright (c) 2018-2019 Mellanox Technologies LTD. All rights reserved.
  *
  *   Redistribution and use in source and binary forms, with or without
  *   modification, are permitted provided that the following conditions
@@ -78,6 +78,10 @@ struct spdk_nvmf_transport_opts {
 	bool		dif_insert_or_strip;
 };
 
+struct spdk_nvmf_poll_group_stat {
+	int dummy;
+};
+
 /**
  * Construct an NVMe-oF target.
  *
@@ -190,6 +194,18 @@ void spdk_nvmf_poll_group_destroy(struct spdk_nvmf_poll_group *group);
 int spdk_nvmf_poll_group_add(struct spdk_nvmf_poll_group *group,
 			     struct spdk_nvmf_qpair *qpair);
 
+/**
+ * Get current poll group statistics.
+ *
+ * \param tgt The NVMf target.
+ * \param stat Pointer to allocated statistics structure to fill with values.
+ *
+ * \return 0 upon success.
+ * \return -EINVAL if either group or stat is NULL.
+ */
+int spdk_nvmf_poll_group_get_stat(struct spdk_nvmf_tgt *tgt,
+				  struct spdk_nvmf_poll_group_stat *stat);
+
 typedef void (*nvmf_qpair_disconnect_cb)(void *ctx);
 
 /**

lib/event/subsystems/nvmf/nvmf_rpc.c

@@ -2,7 +2,7 @@
  *   BSD LICENSE
  *
  *   Copyright (c) Intel Corporation. All rights reserved.
- *   Copyright (c) 2018 Mellanox Technologies LTD. All rights reserved.
+ *   Copyright (c) 2018-2019 Mellanox Technologies LTD. All rights reserved.
  *
  *   Redistribution and use in source and binary forms, with or without
  *   modification, are permitted provided that the following conditions
@@ -1628,3 +1628,72 @@ spdk_rpc_get_nvmf_transports(struct spdk_jsonrpc_request *request,
 	spdk_jsonrpc_end_result(request, w);
 }
 SPDK_RPC_REGISTER("get_nvmf_transports", spdk_rpc_get_nvmf_transports, SPDK_RPC_RUNTIME)
+
+struct rpc_nvmf_get_stats_ctx {
+	struct spdk_jsonrpc_request *request;
+	struct spdk_json_write_ctx *w;
+};
+
+static void
+rpc_nvmf_get_stats_done(struct spdk_io_channel_iter *i, int status)
+{
+	struct rpc_nvmf_get_stats_ctx *ctx = spdk_io_channel_iter_get_ctx(i);
+
+	spdk_json_write_array_end(ctx->w);
+	spdk_json_write_object_end(ctx->w);
+	spdk_jsonrpc_end_result(ctx->request, ctx->w);
+	free(ctx);
+}
+
+static void
+rpc_nvmf_get_stats(struct spdk_io_channel_iter *i)
+{
+	struct rpc_nvmf_get_stats_ctx *ctx = spdk_io_channel_iter_get_ctx(i);
+	struct spdk_nvmf_poll_group_stat stat;
+
+	if (0 == spdk_nvmf_poll_group_get_stat(g_spdk_nvmf_tgt, &stat)) {
+		spdk_json_write_object_begin(ctx->w);
+		spdk_json_write_named_string(ctx->w, "name", spdk_thread_get_name(spdk_get_thread()));
+		spdk_json_write_object_end(ctx->w);
+	}
+
+	spdk_for_each_channel_continue(i, 0);
+}
+
+
+static void
+spdk_rpc_nvmf_get_stats(struct spdk_jsonrpc_request *request,
+			const struct spdk_json_val *params)
+{
+	struct rpc_nvmf_get_stats_ctx *ctx;
+
+	if (params) {
+		spdk_jsonrpc_send_error_response(request, SPDK_JSONRPC_ERROR_INVALID_PARAMS,
+						 "'nvmf_get_stats' requires no arguments");
+		return;
+	}
+
+	ctx = calloc(1, sizeof(*ctx));
+	if (!ctx) {
+		spdk_jsonrpc_send_error_response(request, SPDK_JSONRPC_ERROR_INTERNAL_ERROR,
+						 "Memory allocation error");
+		return;
+	}
+	ctx->request = request;
+
+	ctx->w = spdk_jsonrpc_begin_result(ctx->request);
+	if (NULL == ctx->w) {
+		free(ctx);
+		return;
+	}
+
+	spdk_json_write_object_begin(ctx->w);
+	spdk_json_write_named_array_begin(ctx->w, "poll_groups");
+
+	spdk_for_each_channel(g_spdk_nvmf_tgt,
+			      rpc_nvmf_get_stats,
+			      ctx,
+			      rpc_nvmf_get_stats_done);
+}
+
+SPDK_RPC_REGISTER("nvmf_get_stats", spdk_rpc_nvmf_get_stats, SPDK_RPC_RUNTIME)

lib/nvmf/nvmf.c

@@ -2,7 +2,7 @@
  *   BSD LICENSE
  *
  *   Copyright (c) Intel Corporation. All rights reserved.
- *   Copyright (c) 2018 Mellanox Technologies LTD. All rights reserved.
+ *   Copyright (c) 2018-2019 Mellanox Technologies LTD. All rights reserved.
  *
  *   Redistribution and use in source and binary forms, with or without
  *   modification, are permitted provided that the following conditions
@@ -1227,3 +1227,20 @@ spdk_nvmf_get_optimal_poll_group(struct spdk_nvmf_qpair *qpair)
 
 	return tgroup->group;
 }
+
+int
+spdk_nvmf_poll_group_get_stat(struct spdk_nvmf_tgt *tgt,
+			      struct spdk_nvmf_poll_group_stat *stat)
+{
+	struct spdk_io_channel *ch;
+	struct spdk_nvmf_poll_group *group;
+
+	if (tgt == NULL || stat == NULL) {
+		return -EINVAL;
+	}
+
+	ch = spdk_get_io_channel(tgt);
+	group = spdk_io_channel_get_ctx(ch);
+	*stat = group->stat;
+	return 0;
+}

lib/nvmf/nvmf_internal.h

@@ -1,8 +1,8 @@
 /*-
  *   BSD LICENSE
  *
- *   Copyright (c) Intel Corporation.
- *   All rights reserved.
+ *   Copyright (c) Intel Corporation. All rights reserved.
+ *   Copyright (c) 2019 Mellanox Technologies LTD. All rights reserved.
  *
  *   Redistribution and use in source and binary forms, with or without
  *   modification, are permitted provided that the following conditions
@@ -172,6 +172,9 @@ struct spdk_nvmf_poll_group {
 
 	/* All of the queue pairs that belong to this poll group */
 	TAILQ_HEAD(, spdk_nvmf_qpair)			qpairs;
+
+	/* Statistics */
+	struct spdk_nvmf_poll_group_stat		stat;
 };
 
 typedef enum _spdk_nvmf_request_exec_status {

scripts/rpc.py

@@ -1575,6 +1575,13 @@ Format: 'user:u1 secret:s1 muser:mu1 msecret:ms1,user:u2 secret:s2 muser:mu2 mse
     p.add_argument('-d', '--disable', action='store_true', help='Disable allowing any host')
     p.set_defaults(func=nvmf_subsystem_allow_any_host)
 
+    def nvmf_get_stats(args):
+        print_dict(rpc.nvmf.nvmf_get_stats(args.client))
+
+    p = subparsers.add_parser(
+        'nvmf_get_stats', help='Display current statistics for NVMf subsystem')
+    p.set_defaults(func=nvmf_get_stats)
+
     # pmem
     def create_pmem_pool(args):
         num_blocks = int((args.total_size * 1024 * 1024) / args.block_size)

scripts/rpc/nvmf.py

@@ -323,3 +323,12 @@ def delete_nvmf_subsystem(client, nqn):
     """
     params = {'nqn': nqn}
     return client.call('delete_nvmf_subsystem', params)
+
+
+def nvmf_get_stats(client):
+    """Query NVMf statistics.
+
+    Returns:
+        Current NVMf statistics.
+    """
+    return client.call('nvmf_get_stats')