qemu-e2k/hw/virtio/virtio-blk-pci.c
Stefan Hajnoczi 9445e1e15e virtio-blk-pci: default num_queues to -smp N
Automatically size the number of virtio-blk-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.

Performance improves from 78k to 104k IOPS on a 32 vCPU guest with 101
virtio-blk-pci devices (ioengine=libaio, iodepth=1, bs=4k, rw=randread
with NVMe storage).

Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Cornelia Huck <cohuck@redhat.com>
Reviewed-by: Pankaj Gupta <pankaj.gupta.linux@gmail.com>
Message-Id: <20200818143348.310613-7-stefanha@redhat.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
2020-08-27 08:29:13 -04:00

107 lines
3.2 KiB
C

/*
* Virtio blk PCI Bindings
*
* Copyright IBM, Corp. 2007
* Copyright (c) 2009 CodeSourcery
*
* Authors:
* Anthony Liguori <aliguori@us.ibm.com>
* Paul Brook <paul@codesourcery.com>
*
* This work is licensed under the terms of the GNU GPL, version 2. See
* the COPYING file in the top-level directory.
*
* Contributions after 2012-01-13 are licensed under the terms of the
* GNU GPL, version 2 or (at your option) any later version.
*/
#include "qemu/osdep.h"
#include "hw/qdev-properties.h"
#include "hw/virtio/virtio-blk.h"
#include "virtio-pci.h"
#include "qapi/error.h"
#include "qemu/module.h"
typedef struct VirtIOBlkPCI VirtIOBlkPCI;
/*
* virtio-blk-pci: This extends VirtioPCIProxy.
*/
#define TYPE_VIRTIO_BLK_PCI "virtio-blk-pci-base"
#define VIRTIO_BLK_PCI(obj) \
OBJECT_CHECK(VirtIOBlkPCI, (obj), TYPE_VIRTIO_BLK_PCI)
struct VirtIOBlkPCI {
VirtIOPCIProxy parent_obj;
VirtIOBlock vdev;
};
static Property virtio_blk_pci_properties[] = {
DEFINE_PROP_UINT32("class", VirtIOPCIProxy, class_code, 0),
DEFINE_PROP_BIT("ioeventfd", VirtIOPCIProxy, flags,
VIRTIO_PCI_FLAG_USE_IOEVENTFD_BIT, true),
DEFINE_PROP_UINT32("vectors", VirtIOPCIProxy, nvectors,
DEV_NVECTORS_UNSPECIFIED),
DEFINE_PROP_END_OF_LIST(),
};
static void virtio_blk_pci_realize(VirtIOPCIProxy *vpci_dev, Error **errp)
{
VirtIOBlkPCI *dev = VIRTIO_BLK_PCI(vpci_dev);
DeviceState *vdev = DEVICE(&dev->vdev);
VirtIOBlkConf *conf = &dev->vdev.conf;
if (conf->num_queues == VIRTIO_BLK_AUTO_NUM_QUEUES) {
conf->num_queues = virtio_pci_optimal_num_queues(0);
}
if (vpci_dev->nvectors == DEV_NVECTORS_UNSPECIFIED) {
vpci_dev->nvectors = conf->num_queues + 1;
}
qdev_realize(vdev, BUS(&vpci_dev->bus), errp);
}
static void virtio_blk_pci_class_init(ObjectClass *klass, void *data)
{
DeviceClass *dc = DEVICE_CLASS(klass);
VirtioPCIClass *k = VIRTIO_PCI_CLASS(klass);
PCIDeviceClass *pcidev_k = PCI_DEVICE_CLASS(klass);
set_bit(DEVICE_CATEGORY_STORAGE, dc->categories);
device_class_set_props(dc, virtio_blk_pci_properties);
k->realize = virtio_blk_pci_realize;
pcidev_k->vendor_id = PCI_VENDOR_ID_REDHAT_QUMRANET;
pcidev_k->device_id = PCI_DEVICE_ID_VIRTIO_BLOCK;
pcidev_k->revision = VIRTIO_PCI_ABI_VERSION;
pcidev_k->class_id = PCI_CLASS_STORAGE_SCSI;
}
static void virtio_blk_pci_instance_init(Object *obj)
{
VirtIOBlkPCI *dev = VIRTIO_BLK_PCI(obj);
virtio_instance_init_common(obj, &dev->vdev, sizeof(dev->vdev),
TYPE_VIRTIO_BLK);
object_property_add_alias(obj, "bootindex", OBJECT(&dev->vdev),
"bootindex");
}
static const VirtioPCIDeviceTypeInfo virtio_blk_pci_info = {
.base_name = TYPE_VIRTIO_BLK_PCI,
.generic_name = "virtio-blk-pci",
.transitional_name = "virtio-blk-pci-transitional",
.non_transitional_name = "virtio-blk-pci-non-transitional",
.instance_size = sizeof(VirtIOBlkPCI),
.instance_init = virtio_blk_pci_instance_init,
.class_init = virtio_blk_pci_class_init,
};
static void virtio_blk_pci_register(void)
{
virtio_pci_types_register(&virtio_blk_pci_info);
}
type_init(virtio_blk_pci_register)