virtio specification: OOO completion of the xmit buffers in the networking device
Rusty, hi!
I'd like to ask for a small clarification about the virtio spec.
The virtio specification is put the way that it allows the out-of-order completions in general. Although it states that it's mostly relevant to the virtio-blk it doesn't explicitly bans it for virtio networking devices (for generality?).
(AFAICS the current virtio HV implementations make sure there is no OOO Tx buffers completions).
I wonder if this feature (OOO Tx buffers completions) seems practical to u and if not can I hope that it could be clearly stated in the future virtio specification releases that it's forbidden?
thanks in advance,
vlad
Quoted 6 lines · Vlad Zolotarov
Rusty, hi!
I'd like to ask for a small clarification about the virtio spec. The virtio specification is put the way that it allows the out-of-order completions in general. Although it states that it's mostly relevant to the virtio-blk it doesn't explicitly bans it for virtio networking devices (for generality?).
Indeed.
Quoted 6 lines
(AFAICS the current virtio HV implementations make sure there is no OOO Tx buffers completions).
I wonder if this feature (OOO Tx buffers completions) seems practical to u and if not can I hope that it could be clearly stated in the future virtio specification releases that it's forbidden?
Are you sure that vhost-net doesn't allow async completion already? I can't immediately see why it can't happen, but MST is CC'd.
Cheers,
Rusty.
Quoted 17 lines · Rusty Russell
Quoted 6 lines · Vlad Zolotarov
Rusty, hi!
I'd like to ask for a small clarification about the virtio spec. The virtio specification is put the way that it allows the out-of-order completions in general. Although it states that it's mostly relevant to the virtio-blk it doesn't explicitly bans it for virtio networking devices (for generality?).Indeed.
Quoted 6 lines
(AFAICS the current virtio HV implementations make sure there is no OOO Tx buffers completions).
I wonder if this feature (OOO Tx buffers completions) seems practical to u and if not can I hope that it could be clearly stated in the future virtio specification releases that it's forbidden?
Quoted 5 lines
Are you sure that vhost-net doesn't allow async completion already? I can't immediately see why it can't happen, but MST is CC'd.
Cheers,
Rusty.
vhost-net completes in order but this is just an implementation detail:
this allows keeping a couple of indexes for head/tail instead of tracking requests individually.
We can change this in the future and
guest must allow out of order completions.
Signature · 1 line
MST