Yet another advice appeared on the Multiqueue wiki page: http://www.linux-kvm.org/page/Multiqueue#Enable_MQ_feature We should add vectors=N onto the qemu command line, where N = 2 * (number of queues) + 1. Signed-off-by: Michal Privoznik <mprivozn@redhat.com> --- src/qemu/qemu_command.c | 13 +++++++------ src/qemu/qemu_command.h | 2 +- src/qemu/qemu_hotplug.c | 4 +--- 3 files changed, 9 insertions(+), 10 deletions(-) diff --git a/src/qemu/qemu_command.c b/src/qemu/qemu_command.c index b5ac15a..dbfa0dc 100644 --- a/src/qemu/qemu_command.c +++ b/src/qemu/qemu_command.c @@ -4730,7 +4730,7 @@ qemuBuildNicDevStr(virDomainDefPtr def, virDomainNetDefPtr net, int vlan, int bootindex, - bool multiqueue, + int vhostfdSize, virQEMUCapsPtr qemuCaps) { virBuffer buf = VIR_BUFFER_INITIALIZER; @@ -4783,8 +4783,11 @@ qemuBuildNicDevStr(virDomainDefPtr def, virDomainVirtioEventIdxTypeToString(net->driver.virtio.event_idx)); } } - if (usingVirtio && multiqueue) - virBufferAddLit(&buf, ",mq=on"); + if (usingVirtio && vhostfdSize > 1) { + /* As advised at http://www.linux-kvm.org/page/Multiqueue + * we should add vectors=2*N+1 where N is the vhostfdSize */ + virBufferAsprintf(&buf, ",mq=on,vectors=%d", 2 * vhostfdSize + 1); + } if (vlan == -1) virBufferAsprintf(&buf, ",netdev=host%s", net->info.alias); else @@ -7278,10 +7281,8 @@ qemuBuildInterfaceCommandLine(virCommandPtr cmd, virCommandAddArgList(cmd, "-netdev", host, NULL); } if (virQEMUCapsGet(qemuCaps, QEMU_CAPS_DEVICE)) { - bool multiqueue = tapfdSize > 1 || vhostfdSize > 1; - if (!(nic = qemuBuildNicDevStr(def, net, vlan, bootindex, - multiqueue, qemuCaps))) + vhostfdSize, qemuCaps))) goto cleanup; virCommandAddArgList(cmd, "-device", nic, NULL); } else { diff --git a/src/qemu/qemu_command.h b/src/qemu/qemu_command.h index a9854a3..4761705 100644 --- a/src/qemu/qemu_command.h +++ b/src/qemu/qemu_command.h @@ -102,7 +102,7 @@ char * qemuBuildNicDevStr(virDomainDefPtr def, virDomainNetDefPtr net, int vlan, int bootindex, - bool multiqueue, + int vhostfdSize, virQEMUCapsPtr qemuCaps); char *qemuDeviceDriveHostAlias(virDomainDiskDefPtr disk, diff --git a/src/qemu/qemu_hotplug.c b/src/qemu/qemu_hotplug.c index 9727410..3491fd6 100644 --- a/src/qemu/qemu_hotplug.c +++ b/src/qemu/qemu_hotplug.c @@ -859,10 +859,8 @@ int qemuDomainAttachNetDevice(virConnectPtr conn, } if (virQEMUCapsGet(priv->qemuCaps, QEMU_CAPS_DEVICE)) { - bool multiqueue = tapfdSize > 1 || vhostfdSize > 1; - if (!(nicstr = qemuBuildNicDevStr(vm->def, net, vlan, 0, - multiqueue, priv->qemuCaps))) + vhostfdSize, priv->qemuCaps))) goto try_remove; } else { if (!(nicstr = qemuBuildNicStr(net, NULL, vlan))) -- 1.8.1.5