1. Understanding Citrix HDX Graphics
Citrix TechEdge 2016
Have you ever stayed awake at night wondering if you were giving your users the absolute best experience that you can?
According to the big blue letters we’re going to help put your mind at rest an allow you to get some sleep.
Jeff Traylor
Senior Escalation Engineer

2. Introduction Senior Escalation Engineer Have been at Citrix 4 years
Worked at Cisco (Scientific-Atlanta)
Prior experience as developer, IT Manager, Automation Engineer
Jeff Traylor
I’ve been with Citrix for ~4 years
Prior experience at Cisco (Scientific-Atlanta) playing with IP TV delivery
Have had an assortment of other jobs in the IT field for 30+ years
If it’s legal, involves a computer, and I’m getting paid I would probably try it.

3. Agenda Background HDX graphics display modes HDX graphics use cases
Basic graphics tuning options
Basic troubleshooting tips and tools
Case study and quick fixes
Key takeaways
Q & A
What we are going to talk about today

4. What we are not covering
HDX 3D Pro
Complex topic
Would require a separate 45 minute presentation
Linux VDA
Use your survey to suggest topics
Why we won’t be covering HDX 3D Pro or the Linux VDA due to complexity and time constraints
Please use your survey to suggest it as a future topic

5. The Jargon File XPDM – Windows XP Driver Model
WDDM – Windows Display Driver Model
Kernel Mode
User Mode
DWM - Desktop Window Manager
A few key concepts and terms that you need to know
The oldest driver model is XPDM
WDDM was introduced with Vista and being the transition from …
Kernel Mode drivers run in the kernel memory space – this is why you get BSOD
User Mode drivers – new way of handling drivers, much less prone to taking the whole system down
DWM is what MS added with WDDM and Aero to enable extra functionality
CODEC – enCODer / DECoder

6. Changes to Windows Display Model

7. Changes introduced Desktop OS Version
Windows XP – Introduces XPDM
Windows Vista – Introduces WDDM, DWM, and Aero
Windows 7 – Updates to WDDM 1.1, extends DWM
Windows 8 – Updates to WDDM 1.2, removes XPDM support
Windows 8.1 – Updates to WDDM 1.3
The changes to the Windows Video driver model by version, once Windows 8 hit we no longer get to use XPDM
Windows 10 – Updates to WDDM 2.0

8. Changes introduced by Server OS Version
Server 2003– Introduces XPDM
Server 2008 – Introduces WDDM to Server OS
Server 2008R2 – Updates to WDDM
Server 2012 – Updates to WDDM 2.0, removes XPDM support
Of course the corresponding Server OS’s were updated in step

9. Old display model – prior to DWM
Each program is responsible for it’s own window and draws right into the buffer
Programs need to be aware of overlapping windows
Programs need to be aware of their z-order

10. New display model – with DWM
Each program draws into it’s own off-screen buffer
The Desktop Window manager is responsible for z-order
Allows for Aero effects such as peek and transparency

11. DWM What do these changes enable? Aero Peek
Aero Glass (Transparent Frames)
Windows Flip
Windows Animations
DWM
Because DWM handles the compositing of the desktop new features are available that aren’t when each program has to track it’s own display
Aero Peek in the taskbar
Aero Glass to see the application behind the topmost window
The ability to change orientation easily
A lot of the new Windows animation depend on DWM, including the “Shrink to taskbar” effect

12. What did Citrix change? CTXGFX.EXE User Mode Graphics Driver
Loads Display CODEC
Allows Aero on non-Windows Endpoints
One Weird Little Trick
CTXGFX.EXE
Our good friend CTXGFX.EXE
I’m sure that you’ve met as this is brand new with the 7.x series VDA
First Citrix User Mode driver for graphics
Controls loading the appropriate CODEC
Allows us to present a full Aero desktop to non-Windows endpoints
And One Weird Little Trick – we’ll just leave that teaser there

13. Introducing the HDX Display Modes
Time to “Meet the Modes” that are vying for your attention

14. HDX Display Modes Desktop Composition Redirection (DCR)
H.264 SuperCodec
Compatibility Mode (Thinwire+)
DCR – Current champion of user experience, quite the good looking fellow
H.264 – Great user experience, lower server scalability
Compatibility mode – Good user experience with lower server requirements
Framehawk – the new kid on the block - Good user experience in WAN/WLAN lossy environments
Legacy – the old timer of the bunch - Same as XD 5.6 / XA 6.5
Framehawk
Legacy Graphics

15. Use Case - Desktop Composition Redirection
Most “desktop like” user experience
Users on LAN for high bandwidth
Full Windows PC or high powered Windows thin client as endpoint
Windows 7 or newer VDA
Desktop OS only
Enabled by Policy
Desktop Composition Redirection – “Enabled”
Support for DCR was added to Receiver for Mac in version 12.1
Support for GPU on endpoint was added in Receiver 4.4
Lower stress on the server as a lot of rendering is offloaded to the endpoint
In initial releases of XA/XD 7 this was the default mode, no longer default
NEW
Available for Mac in Receiver 12.1
GPU Acceleration in Receiver for Windows 4.4

16. Use Case – H.264 SuperCodec High definition user experience
Users on LAN or good WAN connection to support bandwidth
Minimum 2 vCPU, 4 vCPU recommended
Windows 7 / Server 2008 or newer VDA
Makes Aero available on any device that can support H.264
Enabled by Policy
Desktop Composition Redirection – “Disabled”
This is now the default mode
H.264 is the same CODEC used in HDX3D Pro, as well as DVDs

17. Use Case – Compatibility Mode (Thinwire+)
Good user experience with light server requirements
Users on LAN or good WAN connection to support bandwidth
Minimum 2 vCPU recommended
Works with older endpoints and Receiver versions
Windows 7 / Server 2008 or newer VDA
Enabled by Policy
Desktop Composition Redirection – “Disabled”
Use Video Codec – “Disabled”
Does NOT use the H.264 CODEC
Based on improvements to Legacy Thinwire

18. Use Case - Framehawk
Provides a good user experience over poor connections
Users on lossy WAN or Wireless connections
Minimum 2 vCPU recommended
Full Windows PC or properly enabled Thin Client or Tablet/Phone
Windows 7 / Server 2008 or newer VDA
Enabled by Policy
Framehawk – “Enabled”
Used in few instances, but when it’s needed it’s there
If the network is dropping >5% packets then Framehawk is a good option

19. Use Case – Legacy Graphics
Good user experience with highest endpoint compatibility
Users on bandwidth constrained connections (low packet loss)
Minimum 1 vCPU recommended
Windows 7 / Server 2008R2 VDA only
Windows 2012 VDA in special circumstances
Enabled by Policy
Legacy Graphics – “Enabled”
Classic Thinwire – the most compatible mode

20. Performance Tuning Options

21. Policy Templates Introduced in XenDesktop / XenApp 7.6 FP3
Introduced in XenApp/XenDesktop 7.6 Feature Pack 3
Performance / quality tuning is a big topic, Citrix recommends using a policy template as a starting point
Full details of each template are contained in the HDX Policy Templates Whitepaper
eDocs - Policy Templates

22. Display Policy Templates
Very High Definition User Experience
High Server Scalability
Optimized for WAN
High Server Scalability – Legacy OS
Each of these templates is defined in the Policy Template whitepaper
The Whitepaper is really the “go to” source for Policy information
Optimized for WAN – Legacy OS

23. Individual Options for Tuning Performance
Detailed information in the Whitepaper on Templates
Additional information in Citrix articles
Important point – not all policies apply to all display modes
Extra performance from Compatibility mode
bandwidth-even-further/
You can get even more tuning options, and here are the resources to find them

24. Basic Troubleshooting
Need to learn long division before getting to use a calculator 

25. Troubleshooting – Detecting Current Display Mode
WMIC Commands
HDX Monitor
Site Graphics Mode Script
Remote Display Analyzer
WMIC – Window Management Interface – the long division method
HDX monitor for an easier way to do the math
Site graphics script to look at your entire site
The “swiss army knife” – Remote Display Analyzer

26. WMIC Commands – Desktop Composition Redirection
Path citrix_virtualchannel_d3d
Event_Message=Composition Redirection has started successfully and Policy_AeroRedirection=TRUE indicates DCR Active

27. WMIC Commands – H.264, Compatibility, Legacy
Path citrix_thinwire
Component_Encoder – DeepCompressionV2Encoder, CompatabilityEncoder
IsActive = Active
IsEnabled = True
Policy_LegacyGraphicsMode = False

28. HDX Monitor Graphics Display
The easier way to do it – HDX Monitor, look at the graphics section
Click on one of the icons to get to the advanced screens with more information

29. HDX Monitor – Desktop Composition Redirection
If using DCR then the Graphics – DCR tab – WMI tab will show that Composition Redirection has started successfully

30. HDX Monitor – H.264
In this case the graphics mode is using H.264 as noted by ‘DeepCompression’
Note that if Legacy mode is enabled, the same information will still be displayed however a warning message will appear at the bottom indicating that this graphics mode is not in use.

31. HDX Monitor – Compatibility Mode
In this case the graphics mode is using H.264 as noted by ‘DeepCompression’
Note that if Legacy mode is enabled, the same information will still be displayed however a warning message will appear at the bottom indicating that this graphics mode is not in use.

32. HDX Monitor – Framehawk
In this case the graphics mode is using H.264 as noted by ‘DeepCompression’
Note that if Legacy mode is enabled, the same information will still be displayed however a warning message will appear at the bottom indicating that this graphics mode is not in use.

33. HDX Monitor – Legacy Graphics
The Thinwire tab which displays Legacy Mode information will also display a warning if it is not enabled.
The warning message on either tab is the simplest way to distinguish whether Legacy Mode is in use.
It is only used if explicitly enabled through policy.

34. View the Site – Site Graphics Mode Script
Site Graphics Mode Script link available in Resources
10000 foot overview of sitewide display modes
Written by a Citrite, but not officially supported

35. RDAnalyzer – a Third Party Tool
Mentioned in many blog posts, including by Citrix bloggers
Written by Barry Schiffer and Bram Wolfs
Not supported by Citrix, community tool
Paid version enables “One Weird Little Trick”
Changing graphics settings and modes on the fly
A great tool created by Bram Wolfs and Barry Schiffer
Paid / Registered version allows for switching display modes on the fly

36. Case Study and Quick Fixes
A quick description of a case, and a couple of tips/fixes for known issues

37. Case Study – Display Performance
A great tool to show graphics performance – the HTML5 Fishbowl
Adjust the parameters on the bottom left, top left shows FPS

38. Case Study – Display Performance
VDA Specs
4 vCPU with 4 Gig RAM
OS – Win7 x64
Hypervisor – VMWare 5.5
Endpoint Specs
HP 620 Thin Client
Discrete graphics chip
2 Gig RAM
Windows 7 Embedded
Customer environment where we saw some performance issues, describing the actual customer setup

39. Case Study – Display Perfomance
Fishbowl on VDA -> thin client – 7 FPS
Fishbowl on VDA -> Windows laptop – 30+ FPS
Fishbowl on VDA (RDP) -> thin client – 7 FPS
Fishbowl on VDA (RDP) – Windows laptop – 30+ FPS
Poor performance in both ICA and RDS
Power management turned off results in 30+ FPS on thin client
Performance was the same in ICA and RDP – good on the laptop and lousy on the thin client
Thin client certainly should have had enough “oomph” to run at the same speed as the laptop
Noticed the Energy Star sticker on the thin client
Turned off Power Management and set everything to “High Performance”
Best guess is that power management was throttling the CPU/GPU between frames
One we disabled power management the performance was the same as the laptop

40. Quick Fix 1 – Applications with blue/purple overlay
Most often seen in Adobe applications
Photoshop
Indesign
Illustrator
Other graphically intense applications can also show the symptom
Registry key is needed to fix
HKEY_LOCAL_MACHINE\SOFTWARE\Citrix\ICA\Thinwire
Create REG_SZ value – “DisableOSSForProcesses”
Set value to list of applications – “photoshop.exe;indesign.exe;illustrator.exe”
Sometimes graphics intensive applications show a blue or purple overlay on the screen
Usually seen with Adobe software
Setting the reg key generally fixes this issue
Issue with “DisableOSSForProcesses” in VDA 7.6FP3, fixed in 7.6CU1

41. Quick Fix 2– Applications don’t redraw correctly
Occurs rarely, but has been seen in some apps
Caused by occasional compatibility issues between the app and the Citrix 3D display driver
Can be fixed by “Blacklisting” the app
xendesktop-blacklisting-an-interim-workaround/
A registry key needs to be created per app to blacklist them
When the application probes for a 3D GPU the driver reports that it does not exist so the app falls back to internal rendering methods
You have likely seen “Enable Hardware Acceleration” option in MS Applications

42. Key Takeaways • The available HDX Display Modes
• HDX Display Mode Use Cases and Basic Tuning Options
• Troubleshooting Tools and Tips
What we, hopefully, were able to convey

43. Q & A

44. Questions Q: How do the settings affect a double-hop?
A: They only affect the connection between one VDA and one Receiver
Do the display modes impact upstream data (i.e. Webcams)?
A: No, those are separate virtual channels
A couple of questions that were asked internally
Audience Q&A

45. Resources eDocs - Thinwire Compatibility Mode
eDocs - Policy Templates
CTX - Group Policy Template Updates for XenApp/XenDesktop
CTX - Whitepaper: HDX Policy Templates

46. Resources
CTX - HDX Graphics Modes - Which Policies Apply to DCT/Thinwire/H An Overview for XenDesktop/XenApp 7.6 FP3
CTX - How to Determine HDX Display Mode
Blogs - Thinwire Compatibility Mode Developers Blog
Blogs - Thinwire Compatibility Tuning

47. Resources - Tools Citrix Site Graphics Utility HDX Monitor
HDX Monitor
Remote Display Analyzer
HTML 5 Fishbowl