Re: [virtio-comment] [PATCH requirements 4/7] net-features: Add notification coalescing requirements

[David Edmondson <david.edmondson@oracle.com>]

On Monday, 2023-07-24 at 06:34:18 +03, Parav Pandit wrote:
> Add virtio net device notification coalescing improvements requirements.
>
> Signed-off-by: Parav Pandit <parav@nvidia.com>

Acked-by: David Edmondson <david.edmondson@oracle.com>

> ---
> changelog:
> v1->v2:
> - addressed comments from Stefan
> - redrafted the requirements to use rearm term and avoid queue enable
>   confusion
> v0->v1:
> - updated the description
> ---
>  net-workstream/features-1.4.md | 11 +++++++++++
>  1 file changed, 11 insertions(+)
>
> diff --git a/net-workstream/features-1.4.md b/net-workstream/features-1.4.md
> index e04727a..27a7886 100644
> --- a/net-workstream/features-1.4.md
> +++ b/net-workstream/features-1.4.md
> @@ -8,6 +8,7 @@ together is desired while updating the virtio net interface.
>  # 2. Summary
>  1. Device counters visible to the driver
>  2. Low latency tx and rx virtqueues for PCI transport
> +3. Virtqueue notification coalescing re-arming support
>  
>  # 3. Requirements
>  ## 3.1 Device counters
> @@ -164,3 +165,13 @@ struct vnet_rx_completion {
>     which can be recycled by the driver when the packets from the completed
>     page is fully consumed.
>  8. The device should be able to consume multiple pages for a receive GSO stream.
> +
> +## 3.3 Virtqueue notification coalescing re-arming support
> +0. Design goal:
> +   a. Avoid constant notifications from the device even in conditions when
> +      the driver may not have acted on the previous pending notification.
> +1. When Tx and Rx virtqueue notification coalescing is enabled, and when such
> +   a notification is reported by the device, the device stops sending further
> +   notifications until the driver rearms the notifications of the virtqueue.
> +2. When the driver rearms the notification of the virtqueue, the device
> +   to notify again if notification coalescing conditions are met.
-- 
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