Windows 10 in VDI: The graphics offload

Posted on Thursday, October 15, 2015
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By George Swain
Senior Technical Consultant


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This is the first in a series of blog posts that will introduce some of the important considerations concerning migration to Windows 10.

The recent release of Windows 10 spells exciting times ahead.  It’s well documented that few people got on with Windows 8 and rightfully didn’t bother making the migration from Windows 7.  However, with Windows 10 feeling more familiar to the experience of Windows 7, but with the security and performance improvements of Windows 8, it looks set to be an upgrade more organisations will be willing to make.

Like any new software release, few want to be the pioneers, so most organisations will wait until the OS has gone through a few patch cycles before seriously considering embarking on upgrade.  However, Microsoft are keen for people to make the move and look set to incentivise in whichever way they can, such as offering end users at home a free upgrade path for the first year, in an attempt to avoid another XP scenario. As users become more familiar with the OS at home, there will be increased pressure for businesses to follow suit.

As one of Microsoft’s top partners, the hands-on experience we’ve had with the OS has left us feeling that many organisations will have little reason not to move once wider application support is available.  It’s slick and will undoubtedly aid staff productivity, especially when combined with the new edition of Office, which is just around the corner.

There’s a BUT...

But, the bit that isn’t talked about with Windows 10 is that to enjoy the full experience, a step up in graphical processing may be required.  The rich interface that Windows 10 offers is only made possible with sufficient CPU horsepower or as is more commonly the case, graphics offload capabilities integrated into the machine.  Features like live tiles, HTML 5 web-apps and the new look Office 16 are all graphically rich and create demands as a result.

Clearly, how you tackle this really depends on the type of environment you’re operating, so I’ll deal with each in turn.

 

PC-client: Are your clients fat enough?

If you’re going to continue working in a PC-client environment, then you need to be mindful of the endpoints you’re working with.  For more recent PCs, processors should be powerful enough to tackle the demands of Windows 10 and new machines now come complete with integrated graphic processing units (GPU) that remove this burden from the CPU.  However, for organisations running older estates or who are sweating assets over a longer period of time, a hardware audit is probably a prudent exercise as part of your planning to ensure good user experience and driver compatibility.

VDI: GPUs are no longer a question

A virtual desktop environment is more challenging simply because graphic off-load capability is a relatively new phenomenon to the mainstream server industry and x86 virtualisation. Server grade CPUs, such as Intel’s Xeon E5 range do not traditionally contain an intergrated GPU, and only through recent products such as NVIDIA’s GRID and vGPU has it been possible to virtualise graphics. Since there has only really been technical previews of Windows 10, and all GPU VDI tests we could find were aimed at higher end graphical users (CAD/Revit users etc.), we took it upon ourselves to run the OS in our lab environment to generate some benchmarks. This was primarily to see what the effects on CPU performance would be versus the impact of running various forms of graphics offload on a standard task workers desktop session (Web browsing and Office 2013). 

In order to carry out the test, we created four virtual desktops; one without a GPU and three supported with varying degrees of GPU performance.  The user session was scripted to open Word, Excel and Outlook, followed by four tabs in Chrome to browse BBC news and a few other different media rich websites involving some scrolling (over a 20 minute period).  The script involved no video playback, 3D applications or anything else traditionally considered graphically intensive. Essentially, a typical session that might be launched by a typical office worker.  We replicated this in both Citrix and VMware environments.


Listed below are version details and hardware specifications used in the test.

Please note that this article is not intended as a direct comparison between XenDesktop and Horizon View but purely to demonstrate that both products show performance gains when utilising hardware graphics offload.

Server Specification:

Dell R720

CPU

2x Xeon E5-2640 2.5GHz Hex core

Memory

192GB

Network

4x 1Gb Broadcom BCM5720

HBA

2x 8Gb QLogic FC

GPU

2x NVIDIA GRID K2

Hypervisor

ESXi 6.0 

 

Citrix: 

XenDesktop 7.6 (Windows 10 technical preview VDA)

VMware: 

Horizon View 6.1

Desktop Build:

Virtual Desktop

CPU

2 vCPU

Memory

2GB (reserved)

Network

1x VMXNET3

HBA

2x 8Gb QLogic FC

GPU

Desktop 1

No GPU

Desktop 2

vSGA (128MB profile)

Desktop 3

K220Q vGPU Profile

Desktop 4

K260Q vGPU Profile

 

The charts below tell an interesting story (thanks to UberAgent and Splunk Server for reporting, both products are highly recommended).

XenDesktop 7.6

Horizon View 6.1:


(Notes: The CPU utilisation figures for the vSGA enabled desktop in Horizon View 6.1 were close to those of the non-GPU enabled desktop. However as this was utilising technical preview code, we believe this to be a bug which should be rectified with Horizon View 6.2).

Wrap up

With any form of graphic acceleration, we see an almost 20% CPU utilisation saving running even basic office worker tasks. This instantly helps to mitigate against high CPU utilisation, which can cause a host of complications from poor user experience, like choppy video playback and slow application response times, to increasing the chance of hardware failure. It also impacts user density per box, showing that utilising graphics offload can result in requiring less servers overall. Additional server hardware ultimately requires more datacentre real estate, more power and more cooling.  In all, unwelcomed consequences for your infrastructure.

In terms of outfitting your server estate with a virtualisation GPU solution, then arguably the current leader in this field is NVIDIA with their GRID range (AMD have announced their intentions to enter the field). The size of your environment and the apps you’ll be running will determine in large part the amount of off-load capability you put into your servers, however for most environments it won’t need to be much, just enough to ensure some form of acceleration.

No show-stopper

Fat-client or VDI, if you’re going to make the switch to Windows 10 you will need to consider graphics. It’s certainly not a show-stopping challenge, simply an important factor when you’re making your plans. 

To learn more about migrating to Windows 10 talk to your account manager get in touch using the form below. 

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