event: add scheduler_set RPC

Add RPC that allows to change scheduler at runtime.

Change-Id: I008670f5e936bc25a0fbc923b826277d15343273
Signed-off-by: Vitaliy Mysak <vitaliy.mysak@intel.com>
Reviewed-on: https://review.spdk.io/gerrit/c/spdk/spdk/+/3958
Reviewed-by: Tomasz Zawadzki <tomasz.zawadzki@intel.com>
Reviewed-by: Jim Harris <james.r.harris@intel.com>
Tested-by: SPDK CI Jenkins <sys_sgci@intel.com>

doc/jsonrpc.md

@@ -620,6 +620,46 @@ Example response:
 }
 ~~~
 
+## framework_set_scheduler {#rpc_framework_set_scheduler}
+
+Select thread scheduler that will be activated.
+This feature is considered as experimental.
+
+### Parameters
+
+Name                    | Optional | Type        | Description
+----------------------- | -------- | ----------- | -----------
+name                    | Required | string      | Name of a scheduler
+
+### Response
+
+Completion status of the operation is returned as a boolean.
+
+### Example
+
+Example request:
+
+~~~
+{
+  "jsonrpc": "2.0",
+  "method": "framework_set_scheduler",
+  "id": 1,
+  "params": {
+    "name": "static"
+  }
+}
+~~~
+
+Example response:
+
+~~~
+{
+  "jsonrpc": "2.0",
+  "id": 1,
+  "result": true
+}
+~~~
+
 ## thread_get_stats {#rpc_thread_get_stats}
 
 Retrieve current statistics of all the threads.

lib/event/app_rpc.c

@@ -433,6 +433,53 @@ rpc_framework_get_reactors(struct spdk_jsonrpc_request *request,
 
 SPDK_RPC_REGISTER("framework_get_reactors", rpc_framework_get_reactors, SPDK_RPC_RUNTIME)
 
+struct rpc_set_scheduler_ctx {
+	char *name;
+};
+
+static void
+free_rpc_framework_set_scheduler(struct rpc_set_scheduler_ctx *r)
+{
+	free(r->name);
+}
+
+static const struct spdk_json_object_decoder rpc_set_scheduler_decoders[] = {
+	{"name", offsetof(struct rpc_set_scheduler_ctx, name), spdk_json_decode_string},
+};
+
+static void
+rpc_framework_set_scheduler(struct spdk_jsonrpc_request *request,
+			    const struct spdk_json_val *params)
+{
+	struct rpc_set_scheduler_ctx req = {NULL};
+	struct spdk_json_write_ctx *w;
+	int ret;
+
+	ret = spdk_json_decode_object(params, rpc_set_scheduler_decoders,
+				      SPDK_COUNTOF(rpc_set_scheduler_decoders),
+				      &req);
+	if (ret) {
+		spdk_jsonrpc_send_error_response(request, SPDK_JSONRPC_ERROR_INVALID_PARAMS,
+						 "Invalid parameters");
+		goto end;
+	}
+
+	ret = _spdk_scheduler_set(req.name);
+	if (ret) {
+		spdk_jsonrpc_send_error_response(request, SPDK_JSONRPC_ERROR_INTERNAL_ERROR,
+						 spdk_strerror(ret));
+		goto end;
+	}
+
+	w = spdk_jsonrpc_begin_result(request);
+	spdk_json_write_bool(w, true);
+	spdk_jsonrpc_end_result(request, w);
+
+end:
+	free_rpc_framework_set_scheduler(&req);
+}
+SPDK_RPC_REGISTER("framework_set_scheduler", rpc_framework_set_scheduler, SPDK_RPC_STARTUP)
+
 struct rpc_thread_set_cpumask_ctx {
 	struct spdk_jsonrpc_request *request;
 	struct spdk_cpuset cpumask;

scripts/rpc.py

@@ -157,6 +157,15 @@ if __name__ == "__main__":
         'framework_get_reactors', help='Display list of all reactors')
     p.set_defaults(func=framework_get_reactors)
 
+    def framework_set_scheduler(args):
+        rpc.app.framework_set_scheduler(args.client,
+                                        name=args.name)
+
+    p = subparsers.add_parser(
+        'framework_set_scheduler', help='Select thread scheduler that will be activated (experimental)')
+    p.add_argument('name', help="Name of a scheduler")
+    p.set_defaults(func=framework_set_scheduler)
+
     # bdev
     def bdev_set_options(args):
         rpc.bdev.bdev_set_options(args.client,

scripts/rpc/app.py

@@ -37,6 +37,18 @@ def framework_get_reactors(client):
     return client.call('framework_get_reactors')
 
 
+def framework_set_scheduler(client, name):
+    """Select threads scheduler that will be activated.
+
+    Args:
+        name: Name of a scheduler
+    Returns:
+        True or False
+    """
+    params = {'name': name}
+    return client.call('framework_set_scheduler', params)
+
+
 def thread_get_stats(client):
     """Query threads statistics.