[pve-devel] [PATCH qemu-server 1/4] fix #4296: virtio-net: enable packed queues for qemu 7.1
Alexandre Derumier
aderumier at odiso.com
Sun Nov 13 15:37:35 CET 2022
virtio 1.1 have improve virtio multiqueue performance,
with a new implementation called "packed queues".
https://www.redhat.com/en/blog/packed-virtqueue-how-reduce-overhead-virtio
https://archive.fosdem.org/2018/schedule/event/virtio/attachments/slides/2167/export/events/attachments/virtio/slides/2167/fosdem_virtio1_1.pdf
This patch enable it by default for qemu 7.1
This don't break old guests with old virtio 1.0 drivers,
as virtio device/devices are forward/backward compatible.
Signed-off-by: Alexandre Derumier <aderumier at odiso.com>
---
PVE/QemuServer.pm | 10 +++++++---
1 file changed, 7 insertions(+), 3 deletions(-)
diff --git a/PVE/QemuServer.pm b/PVE/QemuServer.pm
index 513a248..2fed06d 100644
--- a/PVE/QemuServer.pm
+++ b/PVE/QemuServer.pm
@@ -1730,7 +1730,7 @@ sub print_pbs_blockdev {
}
sub print_netdevice_full {
- my ($vmid, $conf, $net, $netid, $bridges, $use_old_bios_files, $arch, $machine_type) = @_;
+ my ($vmid, $conf, $net, $netid, $bridges, $use_old_bios_files, $arch, $machine_type, $machine_version) = @_;
my $device = $net->{model};
if ($net->{model} eq 'virtio') {
@@ -1744,6 +1744,9 @@ sub print_netdevice_full {
# and out of each queue plus one config interrupt and control vector queue
my $vectors = $net->{queues} * 2 + 2;
$tmpstr .= ",vectors=$vectors,mq=on";
+ if (min_version($machine_version, 7, 1)) {
+ $tmpstr .= ",packed=on";
+ }
}
$tmpstr .= ",bootindex=$net->{bootindex}" if $net->{bootindex} ;
@@ -4021,7 +4024,7 @@ sub config_to_command {
push @$devices, '-netdev', $netdevfull;
my $netdevicefull = print_netdevice_full(
- $vmid, $conf, $d, $netname, $bridges, $use_old_bios_files, $arch, $machine_type);
+ $vmid, $conf, $d, $netname, $bridges, $use_old_bios_files, $arch, $machine_type, $machine_version);
push @$devices, '-device', $netdevicefull;
}
@@ -4252,11 +4255,12 @@ sub vm_deviceplug {
return if !qemu_netdevadd($vmid, $conf, $arch, $device, $deviceid);
my $machine_type = PVE::QemuServer::Machine::qemu_machine_pxe($vmid, $conf);
+ my $machine_version = PVE::QemuServer::Machine::extract_version($machine_type);
my $use_old_bios_files = undef;
($use_old_bios_files, $machine_type) = qemu_use_old_bios_files($machine_type);
my $netdevicefull = print_netdevice_full(
- $vmid, $conf, $device, $deviceid, undef, $use_old_bios_files, $arch, $machine_type);
+ $vmid, $conf, $device, $deviceid, undef, $use_old_bios_files, $arch, $machine_type, $machine_version);
qemu_deviceadd($vmid, $netdevicefull);
eval {
qemu_deviceaddverify($vmid, $deviceid);
--
2.30.2
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