Re: Very slow and inconsistent internal network speed (between, VM's on the same host) for FreeBSD 11.0+ as guest on, XCP-ng/XenServer

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Re: Very slow and inconsistent internal network speed (between, VM's on the same host) for FreeBSD 11.0+ as guest on, XCP-ng/XenServer

Karl Pielorz-2


--On 04 July 2019 09:23 +0200 Roger Pau Monné <[hidden email]> wrote:

> As a workaround you can switch to the emulated network card by
> setting 'hw.xen.disable_pv_nics=1' in /boot/loader.conf. That will
> give you worse performance than a fully working PV network card, but
> at least should be consistent. There are others that have switched to
> virtio-net, but I have no idea how to do that with XCP.

Just to add my $0.02's to the conversation...

As Roger knows we've had numerous issues with Xen xn based networking and
FreeBSD guests over the years. We currently run VirtIO (vtnet) on XenServer
7.1 and it solves all these issues (it's probably not quite as 'performant'
as xn - but it's close for what we're using it with - it is miles better
than e1000 performance).

Unfortunately in XenServer 7.6 virtio is no longer compiled into Qemu from
what I can see. XCP-ng has the same issue (as it's based on XenServer) - so
virtio is currently not an option with XCP-ng either.

e1000/rtl8139 will solve 'weirdness' (think of VM's routing traffic, doing
DHCP or VPN duties) - but virtio solves the same issues, with much better
performance.

I've posted to the XCP-ng forums asking if virtio can be enabled in XCP-ng
builds (as this is probably more likely that getting XenServer to release
with it enabled).

Aside from getting Xen xn 'fixed' for the cases it currently fails (no
small undertaking from what I understand) - it leaves FreeBSD pretty much
stuck, at least for some usage cases.


Regards,

-Karl
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Re: Very slow and inconsistent internal network speed (between, VM's on the same host) for FreeBSD 11.0+ as guest on, XCP-ng/XenServer

Christian Marcos
In reply to this post by Roger Pau Monné
From my tests I found that 10.4-RELEASE was as fast as you could expect
(>10Gbit/s), then something changed in 11.0-RELEASE and carried on and got
even worse in 12.0-RELEASE. Would it not be a good idea to begin there
(10.4 -> 11.0), and try to identify what changes could impact the
performance drop so significantly? This is perhaps a much harder task than
it sounds for someone that knows nothing about what changes was made, and
how difficult it would be to identify what changes actually could be
relevant. Just a thought.

Regards,
Christian

Den tors 4 juli 2019 kl 10:39 skrev Karl Pielorz <[hidden email]>:

>
>
> --On 04 July 2019 09:23 +0200 Roger Pau Monné <[hidden email]>
> wrote:
>
> > As a workaround you can switch to the emulated network card by
> > setting 'hw.xen.disable_pv_nics=1' in /boot/loader.conf. That will
> > give you worse performance than a fully working PV network card, but
> > at least should be consistent. There are others that have switched to
> > virtio-net, but I have no idea how to do that with XCP.
>
> Just to add my $0.02's to the conversation...
>
> As Roger knows we've had numerous issues with Xen xn based networking and
> FreeBSD guests over the years. We currently run VirtIO (vtnet) on
> XenServer
> 7.1 and it solves all these issues (it's probably not quite as
> 'performant'
> as xn - but it's close for what we're using it with - it is miles better
> than e1000 performance).
>
> Unfortunately in XenServer 7.6 virtio is no longer compiled into Qemu from
> what I can see. XCP-ng has the same issue (as it's based on XenServer) -
> so
> virtio is currently not an option with XCP-ng either.
>
> e1000/rtl8139 will solve 'weirdness' (think of VM's routing traffic, doing
> DHCP or VPN duties) - but virtio solves the same issues, with much better
> performance.
>
> I've posted to the XCP-ng forums asking if virtio can be enabled in XCP-ng
> builds (as this is probably more likely that getting XenServer to release
> with it enabled).
>
> Aside from getting Xen xn 'fixed' for the cases it currently fails (no
> small undertaking from what I understand) - it leaves FreeBSD pretty much
> stuck, at least for some usage cases.
>
>
> Regards,
>
> -Karl
>
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