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List:       openbsd-misc
Subject:    Re: KVM Q35 Virtual Machines , SR-IOV PCI-E Bridges and OpenBSD jitter on attached network
From:       Tom Smyth <tom.smyth () wirelessconnect ! eu>
Date:       2019-12-28 16:58:08
Message-ID: CAJ3iMJTVZTqYUtW2EG4JN5WxaQCtCM3yGiagmGeRucSboxF=3A () mail ! gmail ! com
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Hello just to follow up on this thread,

I tested  the following

I setup OpenBSD 6.6 Release on  Proxmox 6.1 with an intel 82599ES 10G nic
physical function pass through and there was no issues with jitter at all..

so the issue with jitter and SR-IOV seems to be confined to the
iavf(4) / ixl(4) type nics

Thanks
Tom Smyth

On Tue, 17 Dec 2019 at 05:31, Tom Smyth <tom.smyth@wirelessconnect.eu> wrote:
>
> Hello,
>
> I tried SR-IOV and intel I350 1Gb/s nic  hardware being passed through
> to OpenBSD 6.6 amd64
> the intel i350 passed through as a physical function on PCI-E is
> detected as an em(4) nic
>  and these dont suffer from  the same jitter as the IXL(4) or the
> AVF(4) drivers
>
> so i'm thinking there is something different in the way that em(4)
> interacts with the SRIOV Bridge
> vs the ixl(4) avf(4)  interacting wih the same SRIOV Bridge
>
> later this week some hardware with ix(4) type 10G nics will come
> available and I will try with them ..
>
>
>
>
>
>
>
>
> On Mon, 4 Nov 2019 at 01:04, Tom Smyth <tom.smyth@wirelessconnect.eu> wrote:
> >
> > Hello,
> > Has anyone seen jitter   from 0.5ms to 500ms
> >  on PCI-E attached (SR-IOV) Physical function / virtual function
> > Network interfaces on OpenBSD  Machines running on
> > a KVM  Virtual machine type (Q35)  ?
> >
> > any tips for diagnosing what is causing the jitter ?
> > I have ruled out the driver Ixl  by comparing physical / bare metal
> > performance vs
> > performance when the physical function  of the nic is passed through
> > to the KVM Q35 guest
> >
> > I have also ruled out the hypervisor as centos Guest VMs running with
> > the same hardware don't suffer from the jitter issue
> >
> >
> >
> > --
> > Kindest regards,
> > Tom Smyth.
>
>
>
> --
> Kindest regards,
> Tom Smyth.



-- 
Kindest regards,
Tom Smyth.

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