virtio-scsi-pci: default num_queues to -smp N

Automatically size the number of virtio-scsi-pci, vhost-scsi-pci, and
vhost-user-scsi-pci request virtqueues to match the number of vCPUs.
Other transports continue to default to 1 request virtqueue.

A 1:1 virtqueue:vCPU mapping 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 <stefanha@redhat.com>
Message-Id: <20200818143348.310613-6-stefanha@redhat.com>
Reviewed-by: Cornelia Huck <cohuck@redhat.com>
Reviewed-by: Raphael Norwitz <raphael.norwitz@nutanix.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
This commit is contained in:
Stefan Hajnoczi 2020-08-18 15:33:46 +01:00 committed by Michael S. Tsirkin
parent 4e5163bd84
commit 6a55882284
8 changed files with 37 additions and 13 deletions

View file

@ -28,7 +28,11 @@
#include "hw/mem/nvdimm.h"
#include "migration/vmstate.h"
GlobalProperty hw_compat_5_1[] = {};
GlobalProperty hw_compat_5_1[] = {
{ "vhost-scsi", "num_queues", "1"},
{ "vhost-user-scsi", "num_queues", "1"},
{ "virtio-scsi-device", "num_queues", "1"},
};
const size_t hw_compat_5_1_len = G_N_ELEMENTS(hw_compat_5_1);
GlobalProperty hw_compat_5_0[] = {