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From: Rusty Russell <rusty@rustcorp.com.au>
To: Jason Wang <jasowang@redhat.com>,
	mst@redhat.com, virtualization@lists.linux-foundation.org,
	netdev@vger.kernel.org, linux-kernel@vger.kernel.org
Cc: linux-api@vger.kernel.org, kvm@vger.kernel.org
Subject: Re: [PATCH net-next RFC 1/3] virtio: support for urgent descriptors
Date: Wed, 15 Oct 2014 16:10:02 +1030	[thread overview]
Message-ID: <877g01c2ml.fsf@rustcorp.com.au> (raw)
In-Reply-To: <1413011806-3813-2-git-send-email-jasowang@redhat.com>

Jason Wang <jasowang@redhat.com> writes:
> Below should be useful for some experiments Jason is doing.
> I thought I'd send it out for early review/feedback.
>
> event idx feature allows us to defer interrupts until
> a specific # of descriptors were used.
> Sometimes it might be useful to get an interrupt after
> a specific descriptor, regardless.
> This adds a descriptor flag for this, and an API
> to create an urgent output descriptor.
> This is still an RFC:
> we'll need a feature bit for drivers to detect this,
> but we've run out of feature bits for virtio 0.X.
> For experimentation purposes, drivers can assume
> this is set, or add a driver-specific feature bit.
>
> Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
> Signed-off-by: Jason Wang <jasowang@redhat.com>

The new VRING_DESC_F_URGENT bit is theoretically nicer, but for
networking (which tends to take packets in order) couldn't we just set
the event counter to give us a tx interrupt at the packet we want?

Cheers,
Rusty.

  parent reply	other threads:[~2014-10-15  5:40 UTC|newest]

Thread overview: 18+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2014-10-11  7:16 [PATCH net-next RFC 0/3] virtio-net: Conditionally enable tx interrupt Jason Wang
2014-10-11  7:16 ` [PATCH net-next RFC 1/3] virtio: support for urgent descriptors Jason Wang
2014-10-12  9:27   ` Michael S. Tsirkin
2014-10-13  6:22     ` Jason Wang
2014-10-13  7:16       ` Michael S. Tsirkin
2014-10-15  5:40   ` Rusty Russell [this message]
2014-10-17  5:23     ` Jason Wang
2014-10-11  7:16 ` [PATCH net-next RFC 2/3] vhost: support " Jason Wang
2014-10-11  7:16 ` [PATCH net-next RFC 3/3] virtio-net: conditionally enable tx interrupt Jason Wang
2014-10-11 14:48   ` Eric Dumazet
2014-10-13  6:02     ` Jason Wang
2014-10-14 21:51   ` Michael S. Tsirkin
2014-10-15  3:34     ` Jason Wang
     [not found] ` <1413011806-3813-1-git-send-email-jasowang-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>
2014-10-14 18:53   ` [PATCH net-next RFC 0/3] virtio-net: Conditionally " David Miller
2014-10-14 21:51     ` Michael S. Tsirkin
2014-10-15  3:24       ` Jason Wang
2014-10-14 23:06     ` Michael S. Tsirkin
2014-10-15  7:28       ` Jason Wang

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