Re: [PATCH v4] virtio/vsock: replace virtio_vsock_pkt with sk_buff

[Stefano Garzarella]

On Thu, Nov 24, 2022 at 06:13:49PM +0300, Arseniy Krasnov wrote:
> Hello Stefano
>
> On 24.11.2022 18:00, Stefano Garzarella wrote:
> > This is a net-next material, please remember to use net-next tag:
> > https://www.kernel.org/doc/html/v6.0/process/maintainer-netdev.html#netdev-faq
> >
> > On Wed, Nov 23, 2022 at 10:07:49PM -0800, Bobby Eshleman wrote:
> > > This commit changes virtio/vsock to use sk_buff instead of
> > > virtio_vsock_pkt. Beyond better conforming to other net code, using
> > > sk_buff allows vsock to use sk_buff-dependent features in the future
> > > (such as sockmap) and improves throughput.
> > >
> > > This patch introduces the following performance changes:
> > >
> > > Tool/Config: uperf w/ 64 threads, SOCK_STREAM
> > > Test Runs: 5, mean of results
> > > Before: commit 95ec6bce2a0b ("Merge branch 'net-ipa-more-endpoints'")
> > >
> > > Test: 64KB, g2h
> > > Before: 21.63 Gb/s
> > > After: 25.59 Gb/s (+18%)
> > >
> > > Test: 16B, g2h
> > > Before: 11.86 Mb/s
> > > After: 17.41 Mb/s (+46%)
> > >
> > > Test: 64KB, h2g
> > > Before: 2.15 Gb/s
> > > After: 3.6 Gb/s (+67%)
> > >
> > > Test: 16B, h2g
> > > Before: 14.38 Mb/s
> > > After: 18.43 Mb/s (+28%)
> > >
> > > Signed-off-by: Bobby Eshleman <bobby.eshleman@xxxxxxxxxxxxx>
> > > ---
> >
> > The patch LGTM. I run several tests (iperf3, vsock_test,
> > vsock_diag_test, vhost-user-vsock, tcpdump) and IMO we are okay.
> >
> > I found the following problems that I would like to report:
> >
> > - vhost-user-vsock [1] is failing, but it is not an issue of this patch,
> >   but a spec violation in the rust-vmm/vm-virtio/virtio-vsock crate as I
> >   reported here [2]. We will fix it there, this patch is fine, indeed
> >   trying a guest with the new layout (1 descriptor for both header and
> >   data) with vhost-vsock in Linux 6.0, everything works perfectly.
> >
> > - the new "SOCK_SEQPACKET msg bounds" [3] reworked by Arseniy fails
> >   intermittently with this patch.
> >
> >   Using the tests currently in the kernel tree everything is fine, so
> >   I don't understand if it's a problem in the new test or in this
> >   patch. I've looked at the code again and don't seem to see any
> >   criticisms.
> >
> >   @Arseniy @Bobby can you take a look?
> Seems i've found this problem here:
>
> https://lkml.org/lkml/2022/11/24/708
>
> Being fixed - all tests passes

Good catch!

Thanks,
Stefano