On Mon, Jul 6, 2020 at 7:00 AM Stefan Hajnoczi <stefa...@redhat.com> wrote: > > Automatically size the number of request virtqueues to match the number > of vCPUs. This ensures that completion interrupts are handled on the > same vCPU that submitted the request. No IPI is necessary to complete > an I/O request and performance is improved. The maximum number of MSI-X > vectors and virtqueues limit are respected. > > Signed-off-by: Stefan Hajnoczi <stefa...@redhat.com> > Reviewed-by: Cornelia Huck <coh...@redhat.com> > --- > include/hw/virtio/vhost-user-blk.h | 2 ++ > hw/block/vhost-user-blk.c | 6 +++++- > hw/core/machine.c | 1 + > hw/virtio/vhost-user-blk-pci.c | 4 ++++ > 4 files changed, 12 insertions(+), 1 deletion(-) > > diff --git a/include/hw/virtio/vhost-user-blk.h > b/include/hw/virtio/vhost-user-blk.h > index 34ad6f0c0e..292d17147c 100644 > --- a/include/hw/virtio/vhost-user-blk.h > +++ b/include/hw/virtio/vhost-user-blk.h > @@ -25,6 +25,8 @@ > #define VHOST_USER_BLK(obj) \ > OBJECT_CHECK(VHostUserBlk, (obj), TYPE_VHOST_USER_BLK) > > +#define VHOST_USER_BLK_AUTO_NUM_QUEUES UINT16_MAX > + > typedef struct VHostUserBlk { > VirtIODevice parent_obj; > CharBackend chardev; > diff --git a/hw/block/vhost-user-blk.c b/hw/block/vhost-user-blk.c > index a00b854736..39aec42dae 100644 > --- a/hw/block/vhost-user-blk.c > +++ b/hw/block/vhost-user-blk.c > @@ -420,6 +420,9 @@ static void vhost_user_blk_device_realize(DeviceState > *dev, Error **errp) > return; > } > > + if (s->num_queues == VHOST_USER_BLK_AUTO_NUM_QUEUES) { > + s->num_queues = 1; > + }
What is this check for? Is it just a backstop to ensure that num_queues is set to 1 if vhost-user-blk-pci doesn't update it? > if (!s->num_queues || s->num_queues > VIRTIO_QUEUE_MAX) { > error_setg(errp, "vhost-user-blk: invalid number of IO queues"); > return; > @@ -531,7 +534,8 @@ static const VMStateDescription vmstate_vhost_user_blk = { > > static Property vhost_user_blk_properties[] = { > DEFINE_PROP_CHR("chardev", VHostUserBlk, chardev), > - DEFINE_PROP_UINT16("num-queues", VHostUserBlk, num_queues, 1), > + DEFINE_PROP_UINT16("num-queues", VHostUserBlk, num_queues, > + VHOST_USER_BLK_AUTO_NUM_QUEUES), > DEFINE_PROP_UINT32("queue-size", VHostUserBlk, queue_size, 128), > DEFINE_PROP_BIT("config-wce", VHostUserBlk, config_wce, 0, true), > DEFINE_PROP_END_OF_LIST(), > diff --git a/hw/core/machine.c b/hw/core/machine.c > index 845f6476cb..31bfaacdb5 100644 > --- a/hw/core/machine.c > +++ b/hw/core/machine.c > @@ -30,6 +30,7 @@ > > GlobalProperty hw_compat_5_0[] = { > { "vhost-scsi", "num_queues", "1"}, > + { "vhost-user-blk", "num-queues", "1"}, > { "vhost-user-scsi", "num_queues", "1"}, > { "virtio-balloon-device", "page-poison", "false" }, > { "virtio-blk-device", "num-queues", "1"}, > diff --git a/hw/virtio/vhost-user-blk-pci.c b/hw/virtio/vhost-user-blk-pci.c > index 4f5d5cbf44..a62a71e067 100644 > --- a/hw/virtio/vhost-user-blk-pci.c > +++ b/hw/virtio/vhost-user-blk-pci.c > @@ -54,6 +54,10 @@ static void vhost_user_blk_pci_realize(VirtIOPCIProxy > *vpci_dev, Error **errp) > VHostUserBlkPCI *dev = VHOST_USER_BLK_PCI(vpci_dev); > DeviceState *vdev = DEVICE(&dev->vdev); > > + if (dev->vdev.num_queues == VHOST_USER_BLK_AUTO_NUM_QUEUES) { > + dev->vdev.num_queues = virtio_pci_optimal_num_queues(0); > + } > + > if (vpci_dev->nvectors == DEV_NVECTORS_UNSPECIFIED) { > vpci_dev->nvectors = dev->vdev.num_queues + 1; > } > -- > 2.26.2 >