bdev: add rpc for enabling queue_depth monitoring

Change-Id: Idb5e29b5d5b1d3431fbd1051ccaa6218f9a09600
Signed-off-by: Seth Howell <seth.howell@intel.com>
Reviewed-on: https://review.gerrithub.io/418107
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>
Chandler-Test-Pool: SPDK Automated Test System <sys_sgsw@intel.com>

lib/bdev/rpc/bdev_rpc.c

@@ -452,6 +452,72 @@ invalid:
 }
 SPDK_RPC_REGISTER("delete_bdev", spdk_rpc_delete_bdev, SPDK_RPC_RUNTIME)
 
+struct rpc_set_bdev_qd_sampling_period {
+	char *name;
+	uint64_t period;
+};
+
+static void
+free_rpc_set_bdev_qd_sampling_period(struct rpc_set_bdev_qd_sampling_period *r)
+{
+	free(r->name);
+}
+
+static const struct spdk_json_object_decoder
+	rpc_set_bdev_qd_sampling_period_decoders[] = {
+	{"name", offsetof(struct rpc_set_bdev_qd_sampling_period, name), spdk_json_decode_string},
+	{"period", offsetof(struct rpc_set_bdev_qd_sampling_period, period), spdk_json_decode_uint64},
+};
+
+static void
+spdk_rpc_set_bdev_qd_sampling_period(struct spdk_jsonrpc_request *request,
+				     const struct spdk_json_val *params)
+{
+	struct rpc_set_bdev_qd_sampling_period req = {0};
+	struct spdk_bdev *bdev;
+	struct spdk_json_write_ctx *w;
+
+	req.period = UINT64_MAX;
+
+	if (spdk_json_decode_object(params, rpc_set_bdev_qd_sampling_period_decoders,
+				    SPDK_COUNTOF(rpc_set_bdev_qd_sampling_period_decoders),
+				    &req)) {
+		SPDK_ERRLOG("spdk_json_decode_object failed\n");
+		goto invalid;
+	}
+
+	if (req.name) {
+		bdev = spdk_bdev_get_by_name(req.name);
+		if (bdev == NULL) {
+			SPDK_ERRLOG("bdev '%s' does not exist\n", req.name);
+			goto invalid;
+		}
+	} else {
+		SPDK_ERRLOG("Missing name param\n");
+		goto invalid;
+	}
+
+	if (req.period == UINT64_MAX) {
+		SPDK_ERRLOG("Missing period param");
+	}
+
+	w = spdk_jsonrpc_begin_result(request);
+	spdk_bdev_set_qd_sampling_period(bdev, req.period);
+
+	spdk_json_write_bool(w, true);
+	spdk_jsonrpc_end_result(request, w);
+	free_rpc_set_bdev_qd_sampling_period(&req);
+	return;
+
+invalid:
+	spdk_jsonrpc_send_error_response(request, SPDK_JSONRPC_ERROR_INVALID_PARAMS, "Invalid parameters");
+	free_rpc_set_bdev_qd_sampling_period(&req);
+	return;
+}
+SPDK_RPC_REGISTER("set_bdev_qd_sampling_period",
+		  spdk_rpc_set_bdev_qd_sampling_period,
+		  SPDK_RPC_RUNTIME)
+
 struct rpc_set_bdev_qos_limit_iops {
 	char		*name;
 	uint64_t	ios_per_sec;

scripts/rpc.py

@@ -382,6 +382,19 @@ if __name__ == "__main__":
         'bdev_name', help='Blockdev name to be deleted. Example: Malloc0.')
     p.set_defaults(func=delete_bdev)
 
+    @call_cmd
+    def set_bdev_qd_sampling_period(args):
+        rpc.bdev.set_bdev_qd_sampling_period(args.client,
+                                             name=args.name,
+                                             period=args.period)
+
+    p = subparsers.add_parser('set_bdev_qd_sampling_period', help="Enable or disable tracking of a bdev's queue depth.")
+    p.add_argument('name', help='Blockdev name. Example: Malloc0')
+    p.add_argument('period', help='Period with which to poll the block device queue depth in microseconds.'
+                   ' If set to 0, polling will be disabled.',
+                   type=int)
+    p.set_defaults(func=set_bdev_qd_sampling_period)
+
     @call_cmd
     def set_bdev_qos_limit_iops(args):
         rpc.bdev.set_bdev_qos_limit_iops(args.client,

scripts/rpc/bdev.py

@@ -379,6 +379,20 @@ def bdev_inject_error(client, name, io_type, error_type, num=1):
     return client.call('bdev_inject_error', params)
 
 
+def set_bdev_qd_sampling_period(client, name, period):
+    """Enable queue depth tracking on a specified bdev.
+
+    Args:
+        name: name of a bdev on which to track queue depth.
+        period: period (in microseconds) at which to update the queue depth reading. If set to 0, polling will be disabled.
+    """
+
+    params = {}
+    params['name'] = name
+    params['period'] = period
+    return client.call('set_bdev_qd_sampling_period', params)
+
+
 def set_bdev_qos_limit_iops(client, name, ios_per_sec):
     """Set QoS IOPS limit on a block device.