RE: [Xen-users] RE: VM with PV drivers; Win2003 lock-up

[bart brooks <bart_brooks@xxxxxxxxxxx>]

Hi James

 

Thanks for the quick reply.

Boot device and all swap is on xenvbd.

Bart

> Date: Thu, 7 Aug 2008 09:43:14 +1000
> From: james.harper@xxxxxxxxxxxxxxxx
> To: bart_brooks@xxxxxxxxxxx; xen-users@xxxxxxxxxxxxxxxxxxx
> CC: andy.grover@xxxxxxxxxx; annie.li@xxxxxxxxxx; wayne.gong@xxxxxxxxxx
> Subject: [Xen-users] RE: VM with PV drivers; Win2003 lock-up
>
> Bart,
>
> I hope you don't mind, I have cc'd xen-users as I'll end up repeating
> this there anyway.
>
> > Hi James
> >
> > I'm running the latest windows PV drivers (downloaded and built as
> checked
> > version) on a win2k3 SP2 VM image, which has 4 cpus defined in the xen
> > script. The host is running xen version 3.1.4 on 2.6.18 -
> >
> > The image boots up and runs fine -
> >
> > On the VM added an external storage (volume) via iscsi; the storage is
> > added fine and can be read/written to.
> >
> > When I fire up an iometer test, after about 40 minutes or so the VM no
> > longer answers pings, I can connect to the console via vnc but the
> > pointing device is dead.
> >
> > xm destroyed the VM and re-ran the test under the debugger; using
> another
> > VM to debug the image.
> >
> > When the VM running iometer locks; I am able to break into the
> debugger -
> >
> > But doing step-overs all that seems to run is nt!KiIdleLoop and once
> in
> > awhile nt!PoSetPowerState
> >
> > Questions -
> >
> > Will we get PowerEevents if the system is resource starved ?
> >
> > If so how will the PV drivers handle it ?
>
> Not sure. I haven't implemented any power stuff.
>
> > Have you run into this type of condition before?
>
> Nope.
>
> > Any words of wisdom, etc ...
> >
> > Do you have an unreleased version of the code (drivers), which would
> aid
> > in tracking down this issue?
> >
> > I don't mind running unreleased code -
>
> It's a bit of a tricky time. I have just recently updated the interrupt
> triggering code and unfortunately this has resulted in a huge reduction
> in network performance. Previously the code went:
> (XenPCI IRQ)->(XenPCI Dpc)->(XenNet IRQ)->(XenNet Dpc)
> But now it goes:
> (XenPCI IRQ)->(XenNet IRQ)->(XenNet Dpc)
>
> Which means a huge decrease in latency between getting the interrupt and
> calling of the Dpc where the actual work gets done. The side effect of
> this is that under high network load there is a much smaller amount of
> work to be done per interrupt (less packets built up), and so the per
> packet overhead is much higher. The difference in performance is mainly
> on the RX side of things, and is in the order of a reduction from around
> 800MB/s to 50MB/s. Nasty.
>
> I've just started putting in some code to implement some higher
> efficiencies - basically telling Xen not to interrupt us unless there is
> more than a single packet of work to be done, with a timer to make sure
> that things don't jam up when load reduces and there isn't that much
> work to be done anymore. Once I have that even half working I'll push it
> to hg and you can have a look at it. I've also fixed a bunch of little
> problems along the way that meant that the windows driver verifier was
> crashing all over the place.
>
> None of the above though should cause the problems you are seeing. Is
> your boot device and all swap devices on xenvbd or is it iSCSI too? I
> need to know that before I can offer any suggestions.
>
> Are you sure that iSCSI is causing a problem? Can you get it to crash
> without using iSCSI?
>
> Thanks for the feedback.
>
> James
>
> _______________________________________________
> Xen-users mailing list
> Xen-users@xxxxxxxxxxxxxxxxxxx
> http://lists.xensource.com/xen-users

---

Get Windows Live and get whatever you need, wherever you are. Start here.

_______________________________________________
Xen-users mailing list
Xen-users@xxxxxxxxxxxxxxxxxxx
http://lists.xensource.com/xen-users