rpc: Add thread_get_stats RPC method

SPDK threads collect busy and idle time statistics. This commit adds
thread_get_stats RPC method to retrieve these values.

Signed-off-by: Evgeniy Kochetov <evgeniik@mellanox.com>
Change-Id: I8ed8041c6164eb0c0a9336f4e50b5f26a3f20190
Reviewed-on: https://review.gerrithub.io/c/spdk/spdk/+/445285
Tested-by: SPDK CI Jenkins <sys_sgci@intel.com>
Reviewed-by: Shuhei Matsumoto <shuhei.matsumoto.xt@hitachi.com>
Reviewed-by: Seth Howell <seth.howell5141@gmail.com>
Reviewed-by: Darek Stojaczyk <dariusz.stojaczyk@intel.com>
Reviewed-by: Ben Walker <benjamin.walker@intel.com>
Reviewed-by: Paul Luse <paul.e.luse@intel.com>

CHANGELOG.md

@@ -95,6 +95,10 @@ sock groups. This API is intended to provide the user with that information.
 spdk_sock_group_get_ctx() was added to return the context of the spdk_sock_group.
 spdk_sock_group_create() is updated to allow input the user provided ctx.
 
+### rpc
+
+Added thread_get_stats RPC method to retrieve existing statistics.
+
 ## v19.04:
 
 ### nvme

doc/jsonrpc.md

@@ -484,6 +484,47 @@ Example response:
 }
 ~~~
 
+## thread_get_stats {#rpc_thread_get_stats}
+
+Retrieve current statistics of all the threads.
+
+### Parameters
+
+This method has no parameters.
+
+### Response
+
+The response is an array of objects containing threads statistics.
+
+### Example
+
+Example request:
+~~~
+{
+  "jsonrpc": "2.0",
+  "method": "thread_get_stats",
+  "id": 1
+}
+~~~
+
+Example response:
+~~~
+{
+  "jsonrpc": "2.0",
+  "id": 1,
+  "result": {
+    "tick_rate": 2400000000,
+    "threads": [
+      {
+        "name": "reactor_0",
+        "busy": 139223208,
+        "idle": 8641080608
+      }
+    ]
+  }
+}
+~~~
+
 # Block Device Abstraction Layer {#jsonrpc_components_bdev}
 
 ## set_bdev_options {#rpc_set_bdev_options}

lib/event/rpc/app_rpc.c

@@ -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
@@ -37,6 +37,8 @@
 #include "spdk/rpc.h"
 #include "spdk/string.h"
 #include "spdk/util.h"
+#include "spdk/env.h"
+#include "spdk/thread.h"
 
 #include "spdk_internal/log.h"
 
@@ -153,3 +155,69 @@ spdk_rpc_context_switch_monitor(struct spdk_jsonrpc_request *request,
 }
 
 SPDK_RPC_REGISTER("context_switch_monitor", spdk_rpc_context_switch_monitor, SPDK_RPC_RUNTIME)
+
+struct rpc_thread_get_stats_ctx {
+	struct spdk_jsonrpc_request *request;
+	struct spdk_json_write_ctx *w;
+};
+
+static void
+rpc_thread_get_stats_done(void *arg)
+{
+	struct rpc_thread_get_stats_ctx *ctx = arg;
+
+	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_thread_get_stats(void *arg)
+{
+	struct rpc_thread_get_stats_ctx *ctx = arg;
+	struct spdk_thread_stats stats;
+
+	if (0 == spdk_thread_get_stats(&stats)) {
+		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_named_uint64(ctx->w, "busy", stats.busy_tsc);
+		spdk_json_write_named_uint64(ctx->w, "idle", stats.idle_tsc);
+		spdk_json_write_object_end(ctx->w);
+	}
+}
+
+static void
+spdk_rpc_thread_get_stats(struct spdk_jsonrpc_request *request,
+			  const struct spdk_json_val *params)
+{
+	struct rpc_thread_get_stats_ctx *ctx;
+
+	if (params) {
+		spdk_jsonrpc_send_error_response(request, SPDK_JSONRPC_ERROR_INVALID_PARAMS,
+						 "'thread_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_uint64(ctx->w, "tick_rate", spdk_get_ticks_hz());
+	spdk_json_write_named_array_begin(ctx->w, "threads");
+
+	spdk_for_each_thread(rpc_thread_get_stats, ctx, rpc_thread_get_stats_done);
+}
+
+SPDK_RPC_REGISTER("thread_get_stats", spdk_rpc_thread_get_stats, SPDK_RPC_RUNTIME)

scripts/rpc.py

@@ -1813,6 +1813,13 @@ Format: 'user:u1 secret:s1 muser:mu1 msecret:ms1,user:u2 secret:s2 muser:mu2 mse
     p.add_argument('-n', '--max', help="""Maximum number of notifications to return in response""", type=int)
     p.set_defaults(func=get_notifications)
 
+    def thread_get_stats(args):
+        print_dict(rpc.app.thread_get_stats(args.client))
+
+    p = subparsers.add_parser(
+        'thread_get_stats', help='Display current statistics of all the threads')
+    p.set_defaults(func=thread_get_stats)
+
     def check_called_name(name):
         if name in deprecated_aliases:
             print("{} is deprecated, use {} instead.".format(name, deprecated_aliases[name]), file=sys.stderr)

scripts/rpc/app.py

@@ -21,3 +21,12 @@ def context_switch_monitor(client, enabled=None):
     if enabled is not None:
         params['enabled'] = enabled
     return client.call('context_switch_monitor', params)
+
+
+def thread_get_stats(client):
+    """Query threads statistics.
+
+    Returns:
+        Current threads statistics.
+    """
+    return client.call('thread_get_stats')