From 5a60a3e414ad4a5afd0dd431e8279ee08aa78aad Mon Sep 17 00:00:00 2001
From: Oleg Bondarev <obondarev@mirantis.com>
Date: Fri, 27 Nov 2020 13:37:42 +0400
Subject: [PATCH] Optimize get_ports with QoS extension

Apply qos resource extend func for a full list of ports,
not for each port individually, thus avoiding DB queries for each
individual port.
This should drastically improve port list time in case of many
ports/network with QoS policies assigned.

Change-Id: I1d0b3975ae6e92e34e9da20a0e26ce024422d332
Closes-Bug: #1905726
(cherry picked from commit 2a6fd9d44d8ab1eed038ad1348ed767bd6a6e61a)
---
 neutron/services/qos/qos_plugin.py | 101 +++++++++++++++++++++++------
 1 file changed, 82 insertions(+), 19 deletions(-)

diff --git a/neutron/services/qos/qos_plugin.py b/neutron/services/qos/qos_plugin.py
index ed384488fed..bc52acc974d 100644
--- a/neutron/services/qos/qos_plugin.py
+++ b/neutron/services/qos/qos_plugin.py
@@ -102,6 +102,33 @@ class QoSPlugin(qos.QoSPluginBase):
         if not qos_id:
             return port_res
 
+        if port_res.get('bulk'):
+            port_res['resource_request'] = {
+                'qos_id': qos_id,
+                'network_id': port_db.network_id,
+                'vnic_type': port_res[portbindings.VNIC_TYPE]}
+            return port_res
+
+        min_bw_rules = rule_object.QosMinimumBandwidthRule.get_objects(
+            context.get_admin_context(), qos_policy_id=qos_id)
+        resources = QoSPlugin._get_resources(min_bw_rules)
+        if not resources:
+            return port_res
+
+        segments = network_object.NetworkSegment.get_objects(
+            context.get_admin_context(), network_id=port_db.network_id)
+        traits = QoSPlugin._get_traits(port_res[portbindings.VNIC_TYPE],
+                                       segments)
+        if not traits:
+            return port_res
+
+        port_res['resource_request'] = {
+            'required': traits,
+            'resources': resources}
+        return port_res
+
+    @staticmethod
+    def _get_resources(min_bw_rules):
         resources = {}
         # NOTE(ralonsoh): we should move this translation dict to n-lib.
         rule_direction_class = {
@@ -110,35 +137,71 @@ class QoSPlugin(qos.QoSPluginBase):
             nl_constants.EGRESS_DIRECTION:
                 pl_constants.CLASS_NET_BW_EGRESS_KBPS
         }
-        min_bw_rules = rule_object.QosMinimumBandwidthRule.get_objects(
-            context.get_admin_context(), qos_policy_id=qos_id)
         for rule in min_bw_rules:
             resources[rule_direction_class[rule.direction]] = rule.min_kbps
-        if not resources:
-            return port_res
+        return resources
 
+    @staticmethod
+    def _get_traits(vnic_type, segments):
+        # TODO(lajoskatona): Change to handle all segments when any traits
+        # support will be available. See Placement spec:
+        # https://review.opendev.org/565730
+        first_segment = segments[0]
+        if not first_segment or not first_segment.physical_network:
+            return []
+        physnet_trait = pl_utils.physnet_trait(
+            first_segment.physical_network)
         # NOTE(ralonsoh): we should not rely on the current execution order of
         # the port extending functions. Although here we have
         # port_res[VNIC_TYPE], we should retrieve this value from the port DB
         # object instead.
-        vnic_trait = pl_utils.vnic_type_trait(
-            port_res[portbindings.VNIC_TYPE])
+        vnic_trait = pl_utils.vnic_type_trait(vnic_type)
 
-        # TODO(lajoskatona): Change to handle all segments when any traits
-        # support will be available. See Placement spec:
-        # https://review.opendev.org/565730
-        first_segment = network_object.NetworkSegment.get_objects(
-            context.get_admin_context(), network_id=port_db.network_id)[0]
+        return [physnet_trait, vnic_trait]
 
-        if not first_segment or not first_segment.physical_network:
-            return port_res
-        physnet_trait = pl_utils.physnet_trait(
-            first_segment.physical_network)
+    @staticmethod
+    # TODO(obondarev): use neutron_lib constant
+    @resource_extend.extends(['ports_bulk'])
+    def _extend_port_resource_request_bulk(ports_res, noop):
+        """Add resource request to a list of ports."""
+        min_bw_rules = dict()
+        net_segments = dict()
 
-        port_res['resource_request'] = {
-            'required': [physnet_trait, vnic_trait],
-            'resources': resources}
-        return port_res
+        for port_res in ports_res:
+            if port_res.get('resource_request') is None:
+                continue
+            qos_id = port_res['resource_request'].pop('qos_id', None)
+            if not qos_id:
+                port_res['resource_request'] = None
+                continue
+
+            net_id = port_res['resource_request'].pop('network_id')
+            vnic_type = port_res['resource_request'].pop('vnic_type')
+
+            if qos_id not in min_bw_rules:
+                rules = rule_object.QosMinimumBandwidthRule.get_objects(
+                    context.get_admin_context(), qos_policy_id=qos_id)
+                min_bw_rules[qos_id] = rules
+
+            resources = QoSPlugin._get_resources(min_bw_rules[qos_id])
+            if not resources:
+                continue
+
+            if net_id not in net_segments:
+                segments = network_object.NetworkSegment.get_objects(
+                    context.get_admin_context(),
+                    network_id=net_id)
+                net_segments[net_id] = segments
+
+            traits = QoSPlugin._get_traits(vnic_type, net_segments[net_id])
+            if not traits:
+                continue
+
+            port_res['resource_request'] = {
+                'required': traits,
+                'resources': resources}
+
+        return ports_res
 
     def _get_ports_with_policy(self, context, policy):
         networks_ids = policy.get_bound_networks()