Expose rx/tx_queue_size

Add support for configuring the `rx_queue_size` and `tx_queue_size`
options in the virtio-net driver via nova.conf

Related to nova change: Ib6d4a2d6b9072db42d11ecdde0950cf7a7781944

Change-Id: I71c3988f4a08bce848618555210a6b90415a7f71

manifests/compute/libvirt.pp

@@ -137,6 +137,16 @@
 #   https://libvirt.org/logging.html
 #   Defaults to undef
 #
+# [*rx_queue_size*]
+#   (optional) virtio-net rx queue size
+#   Valid values are 256, 512, 1024
+#   Defaults to $::os_service_default
+#
+# [*tx_queue_size*]
+#   (optional) virtio-net tx queue size
+#   Valid values are 256, 512, 1024
+#   Defaults to $::os_service_default
+#
 class nova::compute::libvirt (
   $ensure_package                             = 'present',
   $libvirt_virt_type                          = 'kvm',
@@ -163,6 +173,8 @@ class nova::compute::libvirt (
   $preallocate_images                         = $::os_service_default,
   $manage_libvirt_services                    = true,
   $log_outputs                                = undef,
+  $rx_queue_size                              = $::os_service_default,
+  $tx_queue_size                              = $::os_service_default,
 ) inherits nova::params {
 
   include ::nova::deps
@@ -199,6 +211,14 @@ class nova::compute::libvirt (
     }
   }
 
+  unless $rx_queue_size == $::os_service_default or $rx_queue_size in [256, 512, 1024] {
+    fail("Invalid rx_queue_size parameter: ${rx_queue_size}")
+  }
+
+  unless $tx_queue_size == $::os_service_default or $tx_queue_size in [256, 512, 1024] {
+    fail("Invalid_tx_queue_size parameter: ${tx_queue_size}")
+  }
+
   # manage_libvirt_services is here for backward compatibility to support
   # deployments that do not include nova::compute::libvirt::services
   #
@@ -234,6 +254,8 @@ class nova::compute::libvirt (
     'libvirt/hw_disk_discard':       value => $libvirt_hw_disk_discard;
     'libvirt/hw_machine_type':       value => $libvirt_hw_machine_type;
     'libvirt/enabled_perf_events':   value => join(any2array($libvirt_enabled_perf_events), ',');
+    'libvirt/rx_queue_size':         value => $rx_queue_size;
+    'libvirt/tx_queue_size':         value => $tx_queue_size;
   }
 
   # cpu_model param is only valid if cpu_mode=custom

releasenotes/notes/rx_tx_queue_size-80a24b35907e4f5e.yaml

@@ -0,0 +1,9 @@
+---
+features:
+  - |
+    Add support for configuring rx/tx queue sizes
+
+    Adds support for configuring the rx_queue_size and tx_queue_size options in the QEMU virtio-net driver by way of nova.conf. Only supported for vhost/vhostuser interfaces.
+    Currently, valid values for the ring buffer sizes are 256, 512, and 1024.
+
+    Adjustable RX queue sizes requires QEMU 2.7.0, and libvirt 2.3.0 (or newer) Adjustable TX queue sizes requires QEMU 2.10.0, and libvirt 3.7.0 (or newer)

spec/classes/nova_compute_libvirt_spec.rb

@@ -60,6 +60,8 @@ describe 'nova::compute::libvirt' do
       it { is_expected.to contain_nova_config('DEFAULT/remove_unused_base_images').with_ensure('absent')}
       it { is_expected.to contain_nova_config('DEFAULT/remove_unused_original_minimum_age_seconds').with_ensure('absent')}
       it { is_expected.to contain_nova_config('libvirt/remove_unused_resized_minimum_age_seconds').with_ensure('absent')}
+      it { is_expected.to contain_nova_config('libvirt/rx_queue_size').with_value('<SERVICE DEFAULT>')}
+      it { is_expected.to contain_nova_config('libvirt/tx_queue_size').with_value('<SERVICE DEFAULT>')}
     end
 
     describe 'with params' do
@@ -83,7 +85,9 @@ describe 'nova::compute::libvirt' do
           :virtlog_service_name                       => 'virtlog',
           :compute_driver                             => 'libvirt.FoobarDriver',
           :preallocate_images                         => 'space',
-          :log_outputs                                => '1:file:/var/log/libvirt/libvirtd.log'
+          :log_outputs                                => '1:file:/var/log/libvirt/libvirtd.log',
+          :rx_queue_size                              => 512,
+          :tx_queue_size                              => 1024,
         }
       end
 
@@ -107,6 +111,8 @@ describe 'nova::compute::libvirt' do
       it { is_expected.to contain_nova_config('DEFAULT/remove_unused_original_minimum_age_seconds').with_value(3600)}
       it { is_expected.to contain_nova_config('libvirt/remove_unused_resized_minimum_age_seconds').with_value(3600)}
       it { is_expected.to contain_libvirtd_config('log_outputs').with_value("\"#{params[:log_outputs]}\"")}
+      it { is_expected.to contain_nova_config('libvirt/rx_queue_size').with_value(512)}
+      it { is_expected.to contain_nova_config('libvirt/tx_queue_size').with_value(1024)}
       it {
         is_expected.to contain_service('libvirt').with(
           :name     => 'custom_service',