diff options
| author | Stefan Hajnoczi <stefanha@redhat.com> | 2020-08-18 15:33:47 +0100 |
|---|---|---|
| committer | Michael S. Tsirkin <mst@redhat.com> | 2020-08-27 08:29:13 -0400 |
| commit | 9445e1e15e66c19e42bea942ba810db28052cd05 (patch) | |
| tree | 04f90ede63d0f327c660fefbbc45f04c610ec429 /include/hw | |
| parent | 6a558822849fab604a1fcb71e7c4e528cafa21d9 (diff) | |
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>
Diffstat (limited to 'include/hw')
| -rw-r--r-- | include/hw/virtio/virtio-blk.h | 2 |
1 files changed, 2 insertions, 0 deletions
diff --git a/include/hw/virtio/virtio-blk.h b/include/hw/virtio/virtio-blk.h index b1334c3904..7539c2b848 100644 --- a/include/hw/virtio/virtio-blk.h +++ b/include/hw/virtio/virtio-blk.h @@ -30,6 +30,8 @@ struct virtio_blk_inhdr unsigned char status; }; +#define VIRTIO_BLK_AUTO_NUM_QUEUES UINT16_MAX + struct VirtIOBlkConf { BlockConf conf; |