On Tue, Mar 11, 2025 at 4:14 AM Bobby Eshleman [off-list ref] wrote:

On Wed, Mar 05, 2025 at 01:46:54PM +0800, Jason Wang wrote:

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On Wed, Mar 5, 2025 at 8:39 AM Bobby Eshleman [off-list ref] wrote:

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On Tue, Apr 28, 2020 at 06:00:52PM +0200, Stefano Garzarella wrote:

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On Tue, Apr 28, 2020 at 04:13:22PM +0800, Jason Wang wrote:

WRT netdev, do we foresee big gains beyond just leveraging the netdev's
namespace?

It's a leverage of the network subsystem (netdevice, steering, uAPI,
tracing, probably a lot of others), not only its namespace. It can
avoid duplicating existing mechanisms in a vsock specific way. If we
manage to do that, namespace support will be a "byproduct".

[...]

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Yes, it can. I think we need to evaluate both approaches (that's why I
raise the approach of reusing netdevice). We can hear from others.

I agree it is worth evaluating. If netdev is being considered, then it
is probably also worth considering your suggestion from a few years back
to add these capabilities by building vsock on top of virtio-net [1].

[1] https://lore.kernel.org/all/2747ac1f-390e-99f9-b24e-f179af79a9da@redhat.com/ (local)

Yes. I think having a dedicated netdev might be simpler than reusing
the virito-net.

Considering that the current vsock protocol will only ever be able to
enjoy a restricted feature set of these other net subsystems due to its
lack of tolerance for packet loss (e.g., no multiqueue steering, no
packet scheduling), I wonder if it would be best to a) wait until a user
requires these capabilities, and b) at that point extend vsock to tolerate
packet loss (add a seqnum)?

Maybe, a question back to this proposal. What's the plan for the
userspace? For example, do we expect to extend iproute2 and other and
how (e.g having a new vsock dedicated tool)?

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Some other thoughts I had: netdev's flow control features would all have
to be ignored or disabled somehow (I think dev_direct_xmit()?), because
queueing introduces packet loss and the vsock protocol is unable to
survive packet loss.

Or just allow it and then configuring a qdisc that may drop packets
could be treated as a misconfiguration.

That is possible, but when I was playing with vsock qdisc the only one
that worked was pfifo_fast/pfifo, as the others that I tested async drop
packets.

I guess it should work with qdiscs with TCQ_F_CAN_BYPASS. Or if it
turns out to be hard we can just bypass the qdisc layer as you said.

Thanks

Thanks,
Bobby