Alex Weeks of vi411.org is liveblogging the sessions he attends at VMworld. He apologizes in advance for the typos.
At first the presenter spoke about basic troubleshooting, and how it
relates to the defined 5 areas. However there was some GREAT
information that came from this session. Here’s a kind of brain dump of
some of the things I took from it …
This was actually a great session. The presenter drilled down into
exactly how VMware has been able to allow the OS to run efficently
without actually running at CPU Ring 0.Typically, Ring 0 is a priveleged mode that the OS runs in.
Applications then run in Ring 3. VMware has been using a technique
called Binary Translation (BT), to allow the OS to run in Ring 0 with
out actually running there. They are then using the concept of Direct
Execution to allow the applicationt to run in Ring 3.What these new CPU virtualition technologies do is create a new CPU
mode called “Root Mode”. This new mode allows the VMM to run at a “Ring
lower” than the Guest OS. Essentually this allow the Guest OS to run in
Ring 0, while the VMM runs below it and eliminates the need for BT.
So far, this has been the best breakout session I’ve attended. The
presenters did a lot of extensive testing of Citrix Presentation Server
inside a VM on both ESX 2.5.X and 3.0.X. …With ESX 2.5.X 80 users ran the CPU at 85%
With ESX 3.0.X 140 users ran the CPU at 80%
(Great Kudo’s for ESX 3.0.X)
The presenters were very clear that they weren’t trying to say you
can get 140 users on a Citrix VM, individual results may vary depending
on what the users are doing. It also shows the performance improvement
from 2.5.X to 3.0.X.
When I heard about VMmark and that there would be a presentation on it
here at VMworld I was very excited. For many of us, proving the
performance capabilities of Virtual Machines within ESX has been a
challenge. We’ve all come up with our own methods of showing how
powerful a Virtual Machine can be. With VMmark, this process is going
to be much easier and more reliable. …VMmark consists of “tiles”. Each “tile” consists of 6 VM’s running
different operating systems and workloads to simulate a complex and
diverse environment. … It’s nice to see this blend of VM’s. This helps show a more realistic
represendation of what a real Virtual Infrastructure might look like.
Although the title was extremely bloated, this session wasn’t. It was
very clear and informative regarding the benefits of multi-core
processors and how newer virtualization features can benefit users. …Although the presentator didn’t go into deep technical detail, he did explain how EPT (Extended Page Tables) will allow the VMM to freely modify the underlying page tables thereby providing optimized access to the Guest OS.
The other virtualization technology that was highlighted was I/O
virtualization. This “defines an architecture for DMA remapping”. This
is going to give the Guest OS direct access to physical hardware device.
