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.
Signed-off-by: Stefan Hajnoczi <stefa...@redhat.com>
---
hw/core/machine.c | 3 +++
hw/scsi/vhost-scsi.c | 3 ++-
hw/scsi/vhost-user-scsi.c | 3 ++-
hw/scsi/virtio-scsi.c | 6 +++++-
hw/virtio/vhost-scsi-pci.c | 10 ++++++++--
hw/virtio/vhost-user-scsi-pci.c | 10 ++++++++--
hw/virtio/virtio-scsi-pci.c | 10 ++++++++--
include/hw/virtio/virtio-scsi.h | 2 ++
8 files changed, 38 insertions(+), 9 deletions(-)
diff --git a/hw/core/machine.c b/hw/core/machine.c
index 9e8c06036f..4bbcec8fbd 100644
--- a/hw/core/machine.c
+++ b/hw/core/machine.c
@@ -33,8 +33,11 @@ GlobalProperty hw_compat_4_2[] = {
{ "virtio-scsi-device", "virtqueue_size", "128"},
{ "virtio-blk-device", "x-enable-wce-if-config-wce", "off" },
{ "virtio-blk-device", "seg-max-adjust", "off"},
+ { "virtio-scsi-device", "num_queues", "1"},
{ "virtio-scsi-device", "seg_max_adjust", "off"},
{ "vhost-blk-device", "seg_max_adjust", "off"},
+ { "vhost-scsi", "num_queues", "1"},
+ { "vhost-user-scsi", "num_queues", "1"},
{ "usb-host", "suppress-remote-wake", "off" },
{ "usb-redir", "suppress-remote-wake", "off" },
{ "qxl", "revision", "4" },
diff --git a/hw/scsi/vhost-scsi.c b/hw/scsi/vhost-scsi.c
index f052377b7e..8cb7e3825f 100644
--- a/hw/scsi/vhost-scsi.c
+++ b/hw/scsi/vhost-scsi.c
@@ -272,7 +272,8 @@ static Property vhost_scsi_properties[] = {
DEFINE_PROP_STRING("vhostfd", VirtIOSCSICommon, conf.vhostfd),
DEFINE_PROP_STRING("wwpn", VirtIOSCSICommon, conf.wwpn),
DEFINE_PROP_UINT32("boot_tpgt", VirtIOSCSICommon, conf.boot_tpgt, 0),
- DEFINE_PROP_UINT32("num_queues", VirtIOSCSICommon, conf.num_queues, 1),
+ DEFINE_PROP_UINT32("num_queues", VirtIOSCSICommon, conf.num_queues,
+ VIRTIO_SCSI_AUTO_NUM_QUEUES),
DEFINE_PROP_UINT32("virtqueue_size", VirtIOSCSICommon, conf.virtqueue_size,
128),
DEFINE_PROP_BOOL("seg_max_adjust", VirtIOSCSICommon, conf.seg_max_adjust,
diff --git a/hw/scsi/vhost-user-scsi.c b/hw/scsi/vhost-user-scsi.c
index e9752baa89..f0a7e76280 100644
--- a/hw/scsi/vhost-user-scsi.c
+++ b/hw/scsi/vhost-user-scsi.c
@@ -163,7 +163,8 @@ static void vhost_user_scsi_unrealize(DeviceState *dev,
Error **errp)
static Property vhost_user_scsi_properties[] = {
DEFINE_PROP_CHR("chardev", VirtIOSCSICommon, conf.chardev),
DEFINE_PROP_UINT32("boot_tpgt", VirtIOSCSICommon, conf.boot_tpgt, 0),
- DEFINE_PROP_UINT32("num_queues", VirtIOSCSICommon, conf.num_queues, 1),
+ DEFINE_PROP_UINT32("num_queues", VirtIOSCSICommon, conf.num_queues,
+ VIRTIO_SCSI_AUTO_NUM_QUEUES),
DEFINE_PROP_UINT32("virtqueue_size", VirtIOSCSICommon, conf.virtqueue_size,
128),
DEFINE_PROP_UINT32("max_sectors", VirtIOSCSICommon, conf.max_sectors,
diff --git a/hw/scsi/virtio-scsi.c b/hw/scsi/virtio-scsi.c
index 427ad83c50..3bf97836d9 100644
--- a/hw/scsi/virtio-scsi.c
+++ b/hw/scsi/virtio-scsi.c
@@ -891,6 +891,9 @@ void virtio_scsi_common_realize(DeviceState *dev,
virtio_init(vdev, "virtio-scsi", VIRTIO_ID_SCSI,
sizeof(VirtIOSCSIConfig));
+ if (s->conf.num_queues == VIRTIO_SCSI_AUTO_NUM_QUEUES) {
+ s->conf.num_queues = 1;
+ }
if (s->conf.num_queues == 0 ||
s->conf.num_queues > VIRTIO_QUEUE_MAX - VIRTIO_SCSI_VQ_NUM_FIXED) {
error_setg(errp, "Invalid number of queues (= %" PRIu32 "), "
@@ -964,7 +967,8 @@ static void virtio_scsi_device_unrealize(DeviceState *dev,
Error **errp)
}
static Property virtio_scsi_properties[] = {
- DEFINE_PROP_UINT32("num_queues", VirtIOSCSI, parent_obj.conf.num_queues,
1),
+ DEFINE_PROP_UINT32("num_queues", VirtIOSCSI, parent_obj.conf.num_queues,
+ VIRTIO_SCSI_AUTO_NUM_QUEUES),
DEFINE_PROP_UINT32("virtqueue_size", VirtIOSCSI,
parent_obj.conf.virtqueue_size, 256),
DEFINE_PROP_BOOL("seg_max_adjust", VirtIOSCSI,
diff --git a/hw/virtio/vhost-scsi-pci.c b/hw/virtio/vhost-scsi-pci.c
index 5dce640eaf..a0b7cdc1ac 100644
--- a/hw/virtio/vhost-scsi-pci.c
+++ b/hw/virtio/vhost-scsi-pci.c
@@ -17,6 +17,7 @@
#include "qemu/osdep.h"
#include "standard-headers/linux/virtio_pci.h"
+#include "hw/boards.h"
#include "hw/qdev-properties.h"
#include "hw/virtio/vhost-scsi.h"
#include "qapi/error.h"
@@ -47,10 +48,15 @@ static void vhost_scsi_pci_realize(VirtIOPCIProxy
*vpci_dev, Error **errp)
{
VHostSCSIPCI *dev = VHOST_SCSI_PCI(vpci_dev);
DeviceState *vdev = DEVICE(&dev->vdev);
- VirtIOSCSICommon *vs = VIRTIO_SCSI_COMMON(vdev);
+ VirtIOSCSIConf *conf = &dev->vdev.parent_obj.parent_obj.conf;
+
+ /* 1:1 vq to vcpu mapping is ideal because it avoids IPIs */
+ if (conf->num_queues == VIRTIO_SCSI_AUTO_NUM_QUEUES) {
+ conf->num_queues = current_machine->smp.cpus;
+ }
if (vpci_dev->nvectors == DEV_NVECTORS_UNSPECIFIED) {
- vpci_dev->nvectors = vs->conf.num_queues + 3;
+ vpci_dev->nvectors = conf->num_queues + VIRTIO_SCSI_VQ_NUM_FIXED + 1;
}
qdev_set_parent_bus(vdev, BUS(&vpci_dev->bus));
diff --git a/hw/virtio/vhost-user-scsi-pci.c b/hw/virtio/vhost-user-scsi-pci.c
index 32febb2daa..2787123c8d 100644
--- a/hw/virtio/vhost-user-scsi-pci.c
+++ b/hw/virtio/vhost-user-scsi-pci.c
@@ -18,6 +18,7 @@
#include "qemu/osdep.h"
#include "standard-headers/linux/virtio_pci.h"
+#include "hw/boards.h"
#include "hw/virtio/vhost-user-scsi.h"
#include "hw/virtio/virtio.h"
#include "hw/virtio/virtio-scsi.h"
@@ -53,10 +54,15 @@ static void vhost_user_scsi_pci_realize(VirtIOPCIProxy
*vpci_dev, Error **errp)
{
VHostUserSCSIPCI *dev = VHOST_USER_SCSI_PCI(vpci_dev);
DeviceState *vdev = DEVICE(&dev->vdev);
- VirtIOSCSICommon *vs = VIRTIO_SCSI_COMMON(vdev);
+ VirtIOSCSIConf *conf = &dev->vdev.parent_obj.parent_obj.conf;
+
+ /* 1:1 vq to vcpu mapping is ideal because it avoids IPIs */
+ if (conf->num_queues == VIRTIO_SCSI_AUTO_NUM_QUEUES) {
+ conf->num_queues = current_machine->smp.cpus;
+ }
if (vpci_dev->nvectors == DEV_NVECTORS_UNSPECIFIED) {
- vpci_dev->nvectors = vs->conf.num_queues + 3;
+ vpci_dev->nvectors = conf->num_queues + VIRTIO_SCSI_VQ_NUM_FIXED + 1;
}
qdev_set_parent_bus(vdev, BUS(&vpci_dev->bus));
diff --git a/hw/virtio/virtio-scsi-pci.c b/hw/virtio/virtio-scsi-pci.c
index e82e7e5680..45618ed2d1 100644
--- a/hw/virtio/virtio-scsi-pci.c
+++ b/hw/virtio/virtio-scsi-pci.c
@@ -15,6 +15,7 @@
#include "qemu/osdep.h"
+#include "hw/boards.h"
#include "hw/qdev-properties.h"
#include "hw/virtio/virtio-scsi.h"
#include "qemu/module.h"
@@ -46,12 +47,17 @@ static void virtio_scsi_pci_realize(VirtIOPCIProxy
*vpci_dev, Error **errp)
{
VirtIOSCSIPCI *dev = VIRTIO_SCSI_PCI(vpci_dev);
DeviceState *vdev = DEVICE(&dev->vdev);
- VirtIOSCSICommon *vs = VIRTIO_SCSI_COMMON(vdev);
DeviceState *proxy = DEVICE(vpci_dev);
+ VirtIOSCSIConf *conf = &dev->vdev.parent_obj.conf;
char *bus_name;
+ /* 1:1 vq to vcpu mapping is ideal because it avoids IPIs */
+ if (conf->num_queues == VIRTIO_SCSI_AUTO_NUM_QUEUES) {
+ conf->num_queues = current_machine->smp.cpus;
+ }
+
if (vpci_dev->nvectors == DEV_NVECTORS_UNSPECIFIED) {
- vpci_dev->nvectors = vs->conf.num_queues + 3;
+ vpci_dev->nvectors = conf->num_queues + VIRTIO_SCSI_VQ_NUM_FIXED + 1;
}
/*
diff --git a/include/hw/virtio/virtio-scsi.h b/include/hw/virtio/virtio-scsi.h
index 9f293bcb80..c0b8e4dd7e 100644
--- a/include/hw/virtio/virtio-scsi.h
+++ b/include/hw/virtio/virtio-scsi.h
@@ -39,6 +39,8 @@
/* Number of virtqueues that are always present */
#define VIRTIO_SCSI_VQ_NUM_FIXED 2
+#define VIRTIO_SCSI_AUTO_NUM_QUEUES UINT32_MAX
+
typedef struct virtio_scsi_cmd_req VirtIOSCSICmdReq;
typedef struct virtio_scsi_cmd_resp VirtIOSCSICmdResp;
typedef struct virtio_scsi_ctrl_tmf_req VirtIOSCSICtrlTMFReq;
--
2.24.1
