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Sorry for the late response, I've had a
lot to digest.
On 09/21/2012 01:02 PM, Casey DeLorme wrote:
Thanks for the CC Andrew,
I responded in private since I didn't want to spam the
list.
Since we're on the subject of the latest hardware, my
system was using a Z68 Motherboard Chipset and Core i7
SandyBridge CPU (2600). I just sold it to a friend and
upgraded to the latest.
Now running an IvyBridge 3770, Z77 Motherboard Chipset
(ASRock Z77 Extreme 9), and similar components for the rest.
The Extreme 9 price is extremely high, I wouldn't recommend
it unless you have the money, their Z77 Extreme 6 is priced at
the same as the Z68 Extreme4 Gen3, and has all the same
features plus more USB 3.0. I would give that one a shake if
you are looking for newest components. The hardest part of
switching from the Extreme4 Gen3 was remapping the USB ports
to USB controllers by PCI BDF in Linux, because I haven't
found an easy way to do that using the systems information
yet.
Funnily enough, the Extreme9 was one of
my two original motherboard candidates, along with the Gigabyte
G1.Sniper 3. Though I've expanded that list now to include all of
ASRock's Z77 line of motherboards. I might even consider Z77
motherboards from other manufacturers, if I can confirm they
support VT-d.
I've also been contemplating going with a Q77 motherboard, just to
avoid the hassles of determining if a given Z77 motherboard
actually has VT-d support. The downside to the Q77 motherboards I
have looked at is that they typically lack the integrated extras
(e.g. additional SATA/USB controllers) that you find on Z77
motherboards. This makes them less attractive for PCI
passthrough.
Furthermore, a respondent on the Ars Technica threads suggested
that an LGA2011 could be worth a gander. Now, when I started
investigating hardware, I had dismissed this option, mostly
because they were often very expensive (incl. CPU). More
aggravating, the X79 chipset used on desktop LGA2011 motherboards
is not officially sanctioned for VT-d. Given it's placement as a
desktop workstation chipset, the omission of VT-d just pissed me
off. I didn't even bother investigating the possibility that X79
motherboard 'unofficially' supported VT-d. So, in order to get
VT-d on LGA2011, you had to level up to a server motherboard.
Unfortunately, most of the options that had the mix of features I
wanted, ended up being ridiculously expensive, particularly
because those motherboards were designed with dual processors in
mind.
Fortunately, there have been some changes since then. For
example, I found this
Gigabyte motherboard. It's based on the C606 server chipset
but packaged as a desktop motherboard. It is sanctioned by Intel
for VT-d and has more RAM capacity. As an added bonus, it
includes an integrated SAS controller supplying eight SAS 3GB/s
ports. I'm pretty sure it's fake RAID though. No big deal, I'll
probably end up using Btrfs, mdadm, or ZFS on that controller
anyway. As things stand now, this motherboard would pretty much
cost the same as the Extreme9. Going the LGA 2011 route, however,
would require I start with two discrete GPUs instead of one.
Maybe something like this,
combined with something like this
or this.
All of these considerations have seriously complicated my
decision-making process. I still haven't managed to pare down my
hardware choices to fit the $2000 budget I have imposed on
myself. And those calculations don't even include one discrete
GPU! So far, most (not all, e.g. Extreme6) of the suggestions I
get haven't helped to reduce costs. Based on your success, I'm
sorely tempted to dip into my reserve fund for building a second,
more modest box: My contingency plan if my experiments in
virtualization failed to produce satisfactory results.
As soon as I'm done putting together the details, I'll
append the new hardware information to the wiki.
As for changes, the new Z77 chipset has onboard USB 3.0 in
exchange for some of the formerly USB 2.0 ports. In my
performance demo video I showed that USB 2.0 speeds are
sub-par, but even SUB 2.0 devices can hit higher rates when
connected to a USB 3.0 port. As far as the IvyBridge CPU,
onboard graphics are noticeably better in Dom0, and file
decompression in my Windows HVM appears to be faster. I have
not run any benchmark tests yet.
I was kind of surprised by that. I can understand that there would
be some overhead due to the virtualized environment, but I wondered
what would cause such a degradation of performance? I mean I know
USB is pretty CPU dependent. However, with a Core i7, I figure
there would be enough CPU cycles to spare that only multiple
asynchronous connections would cause that kind of performance hit.
I compiled the new Xen 4.2 stable, as tagged in the new 4.2
testing branch, but I may try the older revision of Xen in my
guide. I am getting an error on the first-launch attempt of
any virtual machine with passed devices. When I try again it
works, but it's 5 lines worth of errors which makes the
following success seem less joyful.
I tried kernel 3.5.4, and it appears to be suffering the
same passthrough bugs as 3.5.2, so I would avoid 3.5+ still.
I ended up with Kernel 3.4.11, which is working.
I'll keep all that in mind, though I don't have a problem compiling
sever kernel images to play with... BTW, would there be any
significant problems, that you know of, to compiling and trying
several combinations of Linux and Xen during my testing phase? If I
went with significantly different hardware, I imagine I might need
different combinations of both. But, since I haven't actually
gotten to the testing phase, I don't know what easily avoidable
pitfalls might be in my path.
One good bit of news was I kept my SSD, so I was able to
just recreate the HVM configuration and launch Windows without
problems. Only issues were new drivers, and Windows asking to
reactivate due to HW changes.
Hope this information helps,
~Casey
It's all been very helpful. I am in your debt! I'm sure others
will be too, once they make use of your guide.
BTW, another thing that I've been wondering about. Should I treat
Dom0 as an administrative domain and create a separate DomU for my
Linux desktop? Or is it safe to reduce the overhead of having a
Linux DomU and just use Dom0? I know this is probably more of a
stylistic question; after all, you were using your Dom0 for
development purposes... but that's significantly different from a
general purpose desktop environment.
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