Re: [PATCH v2] Limit the amount of work done for each Receiver DPC

["Durrant, Paul" <xadimgnik@xxxxxxxxx>]

On 06/06/2022 13:00, Martin Harvey wrote:
> +    if (!IsListEmpty(&Ring->PacketComplete)) {
> +        // Re-run for the remainder from the back of DPC queue.
> +        Ring->BackPressured = TRUE;
> +        if (KeInsertQueueDpc(&Ring->QueueDpc, NULL, NULL))
> +            Ring->QueueDpcs++;
> +    } else {
> +        Ring->BackPressured = FALSE;
> +
> +        // PollDpc is zeroed before final flush, don't queue it here.
> +        if (!Ring->Flush && KeInsertQueueDpc(&Ring->PollDpc, NULL, NULL))
> +            Ring->PollDpcs++;
> +    }
>   }
>
> Additionally, there's a problem here in your rewrite. We only want to queue the 
> PollDpc when we go from the backpressured to the non-backpressured state. Doing 
> this in the low load case will run the entire PollDpc rx path continuously, 
> which is definitely a mistake.
Yes, that is a mistake.

I'll rebase the 2nd patch on top and let's see how that looks.

  Paul

> MH.