On Tue, Apr 18, 2023 at 3:22 PM Shao-Chien Chiang <ray90...@gmail.com> wrote:
>
> After caching the device status and features, the latency is reduced by 0.059
> sec.
Can you add more details? Like:
* Initial and final time.
* Times that you repeated the experiment to reach for valid means etc.
And I think it is worth splitting this patch in two, one with status
and other with features. If we find a regression it may help to track
it down.
Thanks!
>
> Signed-off-by: Shao-Chien Chiang <ray90...@gmail.com>
> ---
> hw/virtio/vhost-vdpa.c | 16 ++++++++++------
> include/hw/virtio/vhost-vdpa.h | 2 ++
> 2 files changed, 12 insertions(+), 6 deletions(-)
>
> diff --git a/hw/virtio/vhost-vdpa.c b/hw/virtio/vhost-vdpa.c
> index bc6bad23d5..ccde4c7040 100644
> --- a/hw/virtio/vhost-vdpa.c
> +++ b/hw/virtio/vhost-vdpa.c
> @@ -350,14 +350,11 @@ static int vhost_vdpa_call(struct vhost_dev *dev,
> unsigned long int request,
>
> static int vhost_vdpa_add_status(struct vhost_dev *dev, uint8_t status)
> {
> - uint8_t s;
> + struct vhost_vdpa *v = dev->opaque;
> + uint8_t s = v->status;
> int ret;
>
> trace_vhost_vdpa_add_status(dev, status);
> - ret = vhost_vdpa_call(dev, VHOST_VDPA_GET_STATUS, &s);
> - if (ret < 0) {
> - return ret;
> - }
>
> s |= status;
>
> @@ -374,6 +371,7 @@ static int vhost_vdpa_add_status(struct vhost_dev *dev,
> uint8_t status)
> if (!(s & status)) {
> return -EIO;
> }
> + v->status = s;
>
> return 0;
> }
> @@ -436,6 +434,8 @@ static int vhost_vdpa_init(struct vhost_dev *dev, void
> *opaque, Error **errp)
> dev->opaque = opaque ;
> v->listener = vhost_vdpa_memory_listener;
> v->msg_type = VHOST_IOTLB_MSG_V2;
> + v->status = 0;
> + v->features = dev->features;
> vhost_vdpa_init_svq(dev, v);
>
> error_propagate(&dev->migration_blocker, v->migration_blocker);
> @@ -456,6 +456,7 @@ static int vhost_vdpa_init(struct vhost_dev *dev, void
> *opaque, Error **errp)
> return ret;
> }
> vhost_svq_valid_features(features, &dev->migration_blocker);
> + v->features = features;
> }
>
> /*
> @@ -718,6 +719,7 @@ static int vhost_vdpa_reset_device(struct vhost_dev *dev)
> ret = vhost_vdpa_call(dev, VHOST_VDPA_SET_STATUS, &status);
> trace_vhost_vdpa_reset_device(dev, status);
> v->suspended = false;
> + v->status = 0;
> return ret;
> }
>
> @@ -1294,8 +1296,10 @@ static int vhost_vdpa_set_vring_call(struct vhost_dev
> *dev,
> static int vhost_vdpa_get_features(struct vhost_dev *dev,
> uint64_t *features)
> {
> - int ret = vhost_vdpa_get_dev_features(dev, features);
> + struct vhost_vdpa *v = dev->opaque;
> + int ret = 0;
>
> + *features = v->features;
> if (ret == 0) {
> /* Add SVQ logging capabilities */
> *features |= BIT_ULL(VHOST_F_LOG_ALL);
> diff --git a/include/hw/virtio/vhost-vdpa.h b/include/hw/virtio/vhost-vdpa.h
> index c278a2a8de..d563630cc9 100644
> --- a/include/hw/virtio/vhost-vdpa.h
> +++ b/include/hw/virtio/vhost-vdpa.h
> @@ -39,6 +39,8 @@ typedef struct vhost_vdpa {
> MemoryListener listener;
> struct vhost_vdpa_iova_range iova_range;
> uint64_t acked_features;
> + uint64_t features;
> + uint8_t status;
> bool shadow_vqs_enabled;
> /* Vdpa must send shadow addresses as IOTLB key for data queues, not GPA
> */
> bool shadow_data;
> --
> 2.25.1
>
>
