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>

diff --git a/hw/core/machine.c b/hw/core/machine.c
index cf5f2dfaeb34a173b6499e34fc8550b38c3c31f0..9ee2aa0f7b4866a874581b53653dabe69f47a8db 100644 (file)
--- a/hw/core/machine.c
+++ b/hw/core/machine.c
@@ -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[] = {

diff --git a/hw/scsi/vhost-scsi.c b/hw/scsi/vhost-scsi.c
index 13b05af29bc18a6266f2b9f1dc62f40bb6f7b247..a83ffeefc827136bbc4bbb77950f79fd1482f1db 100644 (file)
--- a/hw/scsi/vhost-scsi.c
+++ b/hw/scsi/vhost-scsi.c
@@ -270,7 +270,8 @@ 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 a8b821466f990f5f5fbcf829bae87cdff595973e..7c0631656cc0399038407907162f8ec9b20f98e2 100644 (file)
--- a/hw/scsi/vhost-user-scsi.c
+++ b/hw/scsi/vhost-user-scsi.c
@@ -162,7 +162,8 @@ static void vhost_user_scsi_unrealize(DeviceState *dev)
 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 eecdd05af5ead2406b48d86825c2544f8be20f62..3a71ea7097afe3ae0be5125019a5d4c3bcbcc27a 100644 (file)
--- 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)
 }
 
 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 06e814d30eefd2ad468e139c3b95aaccbc27b9b6..a6bb0dc60de3086e15aa09b441e4c7eb1727d77f 100644 (file)
--- a/hw/virtio/vhost-scsi-pci.c
+++ b/hw/virtio/vhost-scsi-pci.c
@@ -47,11 +47,15 @@ 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;
+
+    if (conf->num_queues == VIRTIO_SCSI_AUTO_NUM_QUEUES) {
+        conf->num_queues =
+            virtio_pci_optimal_num_queues(VIRTIO_SCSI_VQ_NUM_FIXED);
+    }
 
     if (vpci_dev->nvectors == DEV_NVECTORS_UNSPECIFIED) {
-        vpci_dev->nvectors = vs->conf.num_queues +
-                             VIRTIO_SCSI_VQ_NUM_FIXED + 1;
+        vpci_dev->nvectors = conf->num_queues + VIRTIO_SCSI_VQ_NUM_FIXED + 1;
     }
 
     qdev_realize(vdev, BUS(&vpci_dev->bus), errp);

diff --git a/hw/virtio/vhost-user-scsi-pci.c b/hw/virtio/vhost-user-scsi-pci.c
index ab6dfb71a929459909354b4c120e9b862b0ffb2f..25e97ca54e38bba34bee5db82fc4c672e5223dbe 100644 (file)
--- a/hw/virtio/vhost-user-scsi-pci.c
+++ b/hw/virtio/vhost-user-scsi-pci.c
@@ -53,11 +53,15 @@ 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;
+
+    if (conf->num_queues == VIRTIO_SCSI_AUTO_NUM_QUEUES) {
+        conf->num_queues =
+            virtio_pci_optimal_num_queues(VIRTIO_SCSI_VQ_NUM_FIXED);
+    }
 
     if (vpci_dev->nvectors == DEV_NVECTORS_UNSPECIFIED) {
-        vpci_dev->nvectors = vs->conf.num_queues +
-                             VIRTIO_SCSI_VQ_NUM_FIXED + 1;
+        vpci_dev->nvectors = conf->num_queues + VIRTIO_SCSI_VQ_NUM_FIXED + 1;
     }
 
     qdev_realize(vdev, BUS(&vpci_dev->bus), errp);

diff --git a/hw/virtio/virtio-scsi-pci.c b/hw/virtio/virtio-scsi-pci.c
index 3ff9eb7ef65887aadb95478df194ee617256285a..fa4b3bfb501c446a44557814d988dfc4348b587c 100644 (file)
--- a/hw/virtio/virtio-scsi-pci.c
+++ b/hw/virtio/virtio-scsi-pci.c
@@ -46,13 +46,17 @@ 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;
 
+    if (conf->num_queues == VIRTIO_SCSI_AUTO_NUM_QUEUES) {
+        conf->num_queues =
+            virtio_pci_optimal_num_queues(VIRTIO_SCSI_VQ_NUM_FIXED);
+    }
+
     if (vpci_dev->nvectors == DEV_NVECTORS_UNSPECIFIED) {
-        vpci_dev->nvectors = vs->conf.num_queues +
-                             VIRTIO_SCSI_VQ_NUM_FIXED + 1;
+        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 9f293bcb801be448cf4b60564a3fe288ab9d565b..c0b8e4dd7e6c3257fd782b6c06959f4819874179 100644 (file)
--- 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;