Xen users - Mar 2008 - Release 0.8.5 of GPL PV drivers for Windows

I''ve just uploaded 0.8.5. Please uninstall all the 0.8.4 drivers first
or you''ll get BSoD''s on attempting the upgrade. I''m
sure there''s a way
to make this a bit cleaner (eg require a reboot instead of crashing) but
I don''t know how at this point.

Download from http://www.meadowcourt.org/WindowsXenPV-0.8.5.zip

Major changes are:
. TCP large send offload and other performance enhancements
. The system should crash with a BSoD if it fails to ''hide''
the Qemu
Intel IDE device, which is much better than silent corruption.
. Fixes to the above hiding to properly detect the PCI Bus device driver
under non-English languages
. Beginnings of suspend (required for migration). The Suspend part
appears to work, but the resume doesn''t.

I have a feeling that the large send offload stuff is breaking local (eg
inside Dom0''s bridge) communications, as the packets stay
''large'' until
they leave via a physical adapter. Windows doesn''t like receiving
packets larger than the MTU (and Wireshark causes a BSoD). Unless I can
find an alternative I''ll have to have the Windows xennet driver break
them up itself, which might erode any performance benefit.

I''d be grateful if anyone who has posted previous iperf results could
re-test under this version.

Thanks

James

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James Harper schrieb:
> I''ve just uploaded 0.8.5. Please uninstall all the 0.8.4 drivers
first
> or you''ll get BSoD''s on attempting the upgrade.
I''m sure there''s a way
> to make this a bit cleaner (eg require a reboot instead of crashing) but
> I don''t know how at this point.
> 
> Download from http://www.meadowcourt.org/WindowsXenPV-0.8.5.zip
> ...
Bad, thing is that win2008 enforces singed drivers, so someone have to
deal with this, also win2008 dowsn''t seem to have a boot.ini anymore,
so
we have to use bcdedit.

I''ll have a look on these but sounds ugly.

Florian
> ....
> Thanks
> 
> James
> 
> _______________________________________________
> Xen-users mailing list
> Xen-users@lists.xensource.com
> http://lists.xensource.com/xen-users
> 


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On Thu, Mar 13, 2008 at 10:49:14PM +1100, James Harper
wrote:
> I''ve just uploaded 0.8.5. Please uninstall all the 0.8.4 drivers
first
> or you''ll get BSoD''s on attempting the upgrade.
I''m sure there''s a way
> to make this a bit cleaner (eg require a reboot instead of crashing) but
> I don''t know how at this point.
> 
> Download from http://www.meadowcourt.org/WindowsXenPV-0.8.5.zip
> 
> Major changes are:
> . TCP large send offload and other performance enhancements
> . The system should crash with a BSoD if it fails to
''hide'' the Qemu
> Intel IDE device, which is much better than silent corruption.
> . Fixes to the above hiding to properly detect the PCI Bus device driver
> under non-English languages
> . Beginnings of suspend (required for migration). The Suspend part
> appears to work, but the resume doesn''t.
> 
> I have a feeling that the large send offload stuff is breaking local (eg
> inside Dom0''s bridge) communications, as the packets stay
''large'' until
> they leave via a physical adapter. Windows doesn''t like receiving
> packets larger than the MTU (and Wireshark causes a BSoD). Unless I can
> find an alternative I''ll have to have the Windows xennet driver
break
> them up itself, which might erode any performance benefit.
> 
Hmm.. is it possible to set the MTU for xennet? Does it support Jumbo frames 
(MTU 9000)? 

-- Pasi

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On Thursday 13 March 2008 08:54:03 am Pasi Kärkkäinen
wrote:
> Hmm.. is it possible to set the MTU for xennet? Does it support Jumbo
> frames (MTU 9000)?
How good is Windows PMTUDiscovery setting? Will it automatically send 
1492/1500 MTU packets to the internet after a couple of packets, or is my 
router going to be doing the job of assembling & disassembling? Thanx.

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> 
> Hmm.. is it possible to set the MTU for xennet? Does it support Jumbo
> frames (MTU 9000)?
> 
It looks like maybe the Dom0 backend can support it, so changing it in xennet
would just be a matter of changing the .h file.

Everything on Dom0''s bridge, including the physical interface, would
have to support it and have the same MTU though I think.

James

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> James Harper schrieb:
> > I''ve just uploaded 0.8.5. Please uninstall all the 0.8.4
drivers
first
> > or you''ll get BSoD''s on attempting the upgrade.
I''m sure there''s a
way
> > to make this a bit cleaner (eg require a reboot instead of crashing)
but
> > I don''t know how at this point.
> >
> > Download from http://www.meadowcourt.org/WindowsXenPV-0.8.5.zip
> > ...
> 
> Bad, thing is that win2008 enforces singed drivers, so someone have to
> deal with this, also win2008 dowsn''t seem to have a boot.ini
anymore,
so
> we have to use bcdedit.
> 
> I''ll have a look on these but sounds ugly.
I think you can tweak the registry to turn off the signing requirement.

In the long term I may look at the possibility of getting the drivers
signed, but this costs money so I''d have to charge something for the
signed drivers to recoup the costs, unless the amount was tiny. The
source and unsigned drivers would remain free of course.

At this stage, there are definitely a few things in the drivers that
Microsoft would frown upon, so passing the WHQL testing is probably not
possible at this point.

James


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> On Thursday 13 March 2008 08:54:03 am Pasi Kärkkäinen wrote:
> > Hmm.. is it possible to set the MTU for xennet? Does it support Jumbo
> > frames (MTU 9000)?
> 
> How good is Windows PMTUDiscovery setting? Will it automatically send
> 1492/1500 MTU packets to the internet after a couple of packets, or is my
> router going to be doing the job of assembling & disassembling? Thanx.
Windows PMTU is as good as any other OS afaict. Provided the router can send
back a ICMP Fragmentation Required packet, and nothing in between is blocking
it, it should work just fine.

In addition, windows can do a more intelligent discovery where if packets
aren''t getting through and it doesn''t get a response, it will
try sending smaller packets. Whether this is a good thing in the long term is
questionable though, as it just fixes the symptoms and not the problem.

James

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On Thursday 13 March 2008 07:49:14 am James Harper
wrote:
> I have a feeling that the large send offload stuff is breaking local (eg
> inside Dom0''s bridge) communications, as the packets stay
''large'' until
> they leave via a physical adapter. Windows doesn''t like receiving
> packets larger than the MTU (and Wireshark causes a BSoD). Unless I can
> find an alternative I''ll have to have the Windows xennet driver
break
> them up itself, which might erode any performance benefit.
>
> I''d be grateful if anyone who has posted previous iperf results
could
> re-test under this version.
I completely could not establish a tcp connection, with either Windows 
File/Print, IE7, or iperf. Dns seems to work in IE, and iperf worked fine in 
udp mode. I had to copy back the 0.8.4 files.

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> > I''d be grateful if anyone who has posted previous iperf
results
could
> > re-test under this version.
> 
> I completely could not establish a tcp connection, with either Windows
> File/Print, IE7, or iperf. Dns seems to work in IE, and iperf worked
fine
> in
> udp mode. I had to copy back the 0.8.4 files.
Does your backend have tcp offload enabled?

James

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On Thursday 13 March 2008 10:04:17 pm James Harper
wrote:
> Does your backend have tcp offload enabled?
Walk me thru how to set that up. Thanx.

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> On Thursday 13 March 2008 10:04:17 pm James Harper wrote:
> > Does your backend have tcp offload enabled?
> 
> Walk me thru how to set that up. Thanx.
On all my systems it is enabled automagically, so I''m guessing it will
be on yours too.

1. Get the domain id from xm list
2. do xenstore-ls /local/domain/nnn/device/vif (where nnn is the domain
id)
3. in the above step you will be shown the backend path. Do a
xenstore-ls on that too (probably it will be
/local/domain/0/backend/vif/nnn/0)
4. send me the output of 2 and 3.

The relevant bit is ''feature-gso-tcpv4 = "1"''

Thanks

James


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On Fri, Mar 14, 2008 at 11:35:14AM +1100, James Harper
wrote:
> > 
> > Hmm.. is it possible to set the MTU for xennet? Does it support Jumbo
> > frames (MTU 9000)?
> > 
> 
> It looks like maybe the Dom0 backend can support it, so changing it in
xennet would just be a matter of changing the .h file.
> 
Ok. Would it be possible to change this through some setting (registry?) or
config file
in windows? 
> Everything on Dom0''s bridge, including the physical interface,
would have to support it and have the same MTU though I think.
> 
Yep, of course.

So it would be nice if you could enable it in Windows after you have taken care
of dom0 MTU
9000 configuration..

-- Pasi

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James Harper schrieb:
>> James Harper schrieb:
>>> I''ve just uploaded 0.8.5. Please uninstall all the 0.8.4
drivers
> first
>>> or you''ll get BSoD''s on attempting the upgrade.
I''m sure there''s a
> way
>>> to make this a bit cleaner (eg require a reboot instead of
crashing)
> but
>>> I don''t know how at this point.
>>>
>>> Download from http://www.meadowcourt.org/WindowsXenPV-0.8.5.zip
>>> ...
>> Bad, thing is that win2008 enforces singed drivers, so someone have to
>> deal with this, also win2008 dowsn''t seem to have a boot.ini
anymore,
> so
>> we have to use bcdedit.
>>
>> I''ll have a look on these but sounds ugly.
> 
> I think you can tweak the registry to turn off the signing requirement.
> 
> In the long term I may look at the possibility of getting the drivers
> signed, but this costs money so I''d have to charge something for
the
> signed drivers to recoup the costs, unless the amount was tiny. The
> source and unsigned drivers would remain free of course.
> 
> At this stage, there are definitely a few things in the drivers that
> Microsoft would frown upon, so passing the WHQL testing is probably not
> possible at this point.
> 
> James
> 
Ok, i''ve done some code reading yesterday, so i got this.

adding GPLPV using bcdedit enables the drivers, adding 
DISABLE_INTEGRITY_CHECKS make the system booting again.

Currently i''m working on setting both with an easy
configurebootloader.bat.

The blockdev stuff works the system boots and is looks pretty stable.
I performed some hdd reading benchmarks with interesting results, I''ll 
have to check them first, and complete them with write testing.

But one result is clear, using qemu adds the benefit that the dom0 seems 
to use ram caching, so on a quite powerful machine the qemu stuff looks 
partially faster, but i think when i give the dom0 less ram this will 
disappear.

Good is that using the PV blockdev driver there is no significant 
systemload in dom0, with qemu one core runs at 100%.

So, far some testing is needed but when the network stuff works also, 
i''ll have a look on the signing stuff, afaik it must be signed at all, 
not necessarily by microsoft. So I have to check if i could use my sign 
for that, hopeful that DFN or CA-Cert are at least a bit trustworthy ;)

Florian


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