virtio-net: increase defaults rx|tx-queue-size to 1024

This is reducing packet drop on high pps, and also needed for dpdk.

Redhat already have use it by default in rhev and his openstack platform too
since 2019.

I'm using it in production since 6 months, I don't have seen performance regression.

fix: (which ask for custom option, but setting it by default seem fine for me)

https://bugzilla.proxmox.com/show_bug.cgi?id=1546
https://bugzilla.proxmox.com/show_bug.cgi?id=2349
Signed-off-by: Alexandre Derumier <aderumier@odiso.com>

PVE/QemuServer.pm

@@ -1766,6 +1766,11 @@ sub print_netdevice_full {
 	    $tmpstr .= ",packed=on";
 	}
     }
+
+    if (min_version($machine_version, 7, 1) && $net->{model} eq 'virtio'){
+	$tmpstr .= ",rx_queue_size=1024,tx_queue_size=1024";
+    }
+
     $tmpstr .= ",bootindex=$net->{bootindex}" if $net->{bootindex} ;
 
     if (my $mtu = $net->{mtu}) {

test/cfg2cmd/efidisk-on-rbd.conf.cmd

@@ -28,5 +28,5 @@
   -device 'virtio-balloon-pci,id=balloon0,bus=pci.0,addr=0x3,free-page-reporting=on' \
   -iscsi 'initiator-name=iqn.1993-08.org.debian:01:aabbccddeeff' \
   -netdev 'type=tap,id=net0,ifname=tap8006i0,script=/var/lib/qemu-server/pve-bridge,downscript=/var/lib/qemu-server/pve-bridgedown,vhost=on' \
-  -device 'virtio-net-pci,mac=2E:01:68:F9:9C:87,netdev=net0,bus=pci.0,addr=0x12,id=net0,bootindex=300' \
+  -device 'virtio-net-pci,mac=2E:01:68:F9:9C:87,netdev=net0,bus=pci.0,addr=0x12,id=net0,rx_queue_size=1024,tx_queue_size=1024,bootindex=300' \
   -machine 'type=pc+pve0'

test/cfg2cmd/q35-linux-hostpci-multifunction.conf.cmd

@@ -32,5 +32,5 @@
   -device 'virtio-balloon-pci,id=balloon0,bus=pci.0,addr=0x3,free-page-reporting=on' \
   -iscsi 'initiator-name=iqn.1993-08.org.debian:01:aabbccddeeff' \
   -netdev 'type=tap,id=net0,ifname=tap8006i0,script=/var/lib/qemu-server/pve-bridge,downscript=/var/lib/qemu-server/pve-bridgedown,vhost=on' \
-  -device 'virtio-net-pci,mac=2E:01:68:F9:9C:87,netdev=net0,bus=pci.0,addr=0x12,id=net0,bootindex=300' \
+  -device 'virtio-net-pci,mac=2E:01:68:F9:9C:87,netdev=net0,bus=pci.0,addr=0x12,id=net0,rx_queue_size=1024,tx_queue_size=1024,bootindex=300' \
   -machine 'type=q35+pve0'

test/cfg2cmd/q35-linux-hostpci-x-pci-overrides.conf.cmd

@@ -31,5 +31,5 @@
   -device 'virtio-balloon-pci,id=balloon0,bus=pci.0,addr=0x3,free-page-reporting=on' \
   -iscsi 'initiator-name=iqn.1993-08.org.debian:01:aabbccddeeff' \
   -netdev 'type=tap,id=net0,ifname=tap8006i0,script=/var/lib/qemu-server/pve-bridge,downscript=/var/lib/qemu-server/pve-bridgedown,vhost=on' \
-  -device 'virtio-net-pci,mac=2E:01:68:F9:9C:87,netdev=net0,bus=pci.0,addr=0x12,id=net0,bootindex=300' \
+  -device 'virtio-net-pci,mac=2E:01:68:F9:9C:87,netdev=net0,bus=pci.0,addr=0x12,id=net0,rx_queue_size=1024,tx_queue_size=1024,bootindex=300' \
   -machine 'type=q35+pve0'

test/cfg2cmd/q35-linux-hostpci.conf.cmd

@@ -37,5 +37,5 @@
   -device 'virtio-balloon-pci,id=balloon0,bus=pci.0,addr=0x3,free-page-reporting=on' \
   -iscsi 'initiator-name=iqn.1993-08.org.debian:01:aabbccddeeff' \
   -netdev 'type=tap,id=net0,ifname=tap8006i0,script=/var/lib/qemu-server/pve-bridge,downscript=/var/lib/qemu-server/pve-bridgedown,vhost=on' \
-  -device 'virtio-net-pci,mac=2E:01:68:F9:9C:87,netdev=net0,bus=pci.0,addr=0x12,id=net0,bootindex=300' \
+  -device 'virtio-net-pci,mac=2E:01:68:F9:9C:87,netdev=net0,bus=pci.0,addr=0x12,id=net0,rx_queue_size=1024,tx_queue_size=1024,bootindex=300' \
   -machine 'type=q35+pve0'

test/cfg2cmd/q35-simple.conf.cmd

@@ -25,5 +25,5 @@
   -device 'virtio-balloon-pci,id=balloon0,bus=pci.0,addr=0x3,free-page-reporting=on' \
   -iscsi 'initiator-name=iqn.1993-08.org.debian:01:aabbccddeeff' \
   -netdev 'type=tap,id=net0,ifname=tap8006i0,script=/var/lib/qemu-server/pve-bridge,downscript=/var/lib/qemu-server/pve-bridgedown,vhost=on' \
-  -device 'virtio-net-pci,mac=2E:01:68:F9:9C:87,netdev=net0,bus=pci.0,addr=0x12,id=net0,bootindex=300' \
+  -device 'virtio-net-pci,mac=2E:01:68:F9:9C:87,netdev=net0,bus=pci.0,addr=0x12,id=net0,rx_queue_size=1024,tx_queue_size=1024,bootindex=300' \
   -machine 'type=q35+pve0'

test/cfg2cmd/qemu-xhci-7.1.conf.cmd

@@ -33,5 +33,5 @@
   -device 'virtio-balloon-pci,id=balloon0,bus=pci.0,addr=0x3,free-page-reporting=on' \
   -iscsi 'initiator-name=iqn.1993-08.org.debian:01:aabbccddeeff' \
   -netdev 'type=tap,id=net0,ifname=tap8006i0,script=/var/lib/qemu-server/pve-bridge,downscript=/var/lib/qemu-server/pve-bridgedown,vhost=on' \
-  -device 'virtio-net-pci,mac=A2:C0:43:77:08:A1,netdev=net0,bus=pci.0,addr=0x12,id=net0,bootindex=300' \
+  -device 'virtio-net-pci,mac=A2:C0:43:77:08:A1,netdev=net0,bus=pci.0,addr=0x12,id=net0,rx_queue_size=1024,tx_queue_size=1024,bootindex=300' \
   -machine 'type=pc+pve0'

test/cfg2cmd/qemu-xhci-q35-7.1.conf.cmd

@@ -25,5 +25,5 @@
   -device 'virtio-balloon-pci,id=balloon0,bus=pci.0,addr=0x3,free-page-reporting=on' \
   -iscsi 'initiator-name=iqn.1993-08.org.debian:01:aabbccddeeff' \
   -netdev 'type=tap,id=net0,ifname=tap8006i0,script=/var/lib/qemu-server/pve-bridge,downscript=/var/lib/qemu-server/pve-bridgedown,vhost=on' \
-  -device 'virtio-net-pci,mac=A2:C0:43:77:08:A1,netdev=net0,bus=pci.0,addr=0x12,id=net0,bootindex=300' \
+  -device 'virtio-net-pci,mac=A2:C0:43:77:08:A1,netdev=net0,bus=pci.0,addr=0x12,id=net0,rx_queue_size=1024,tx_queue_size=1024,bootindex=300' \
   -machine 'type=pc-q35-7.1+pve0'

test/cfg2cmd/seabios_serial.conf.cmd

@@ -29,5 +29,5 @@
   -drive 'file=/var/lib/vz/images/8006/vm-8006-disk-0.qcow2,if=none,id=drive-scsi0,discard=on,format=qcow2,cache=none,aio=io_uring,detect-zeroes=unmap' \
   -device 'scsi-hd,bus=scsihw0.0,channel=0,scsi-id=0,lun=0,drive=drive-scsi0,id=scsi0,bootindex=100' \
   -netdev 'type=tap,id=net0,ifname=tap8006i0,script=/var/lib/qemu-server/pve-bridge,downscript=/var/lib/qemu-server/pve-bridgedown,vhost=on' \
-  -device 'virtio-net-pci,mac=A2:C0:43:77:08:A0,netdev=net0,bus=pci.0,addr=0x12,id=net0,bootindex=300' \
+  -device 'virtio-net-pci,mac=A2:C0:43:77:08:A0,netdev=net0,bus=pci.0,addr=0x12,id=net0,rx_queue_size=1024,tx_queue_size=1024,bootindex=300' \
   -machine 'smm=off,type=pc+pve0'