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I'm back from my 7-day Eastern Caribbean cruise and of course the first thing on my mind is my Multimedia Virtualization blog! We've just migrated the Citrix blog site to an updated system so I had a few transitional issues to work through, but now I'm ready to share with you Part 2 of my series on optimizing Adobe Flash performance on Citrix Presentation Server. (Click here to read Part 1.)
There's definitely more to optimizing Adobe Flash than configuring SpeedScreen Flash Acceleration ("SpeedFlash") and making sure you have any required hotfixes to handle newer versions of Flash. One of the features of Presentation Server that can have a very substantial positive impact on Flash performance (animations and video) is Queuing & Tossing. This feature shows up in the management console as "Discard queued images which are replaced by other images" or "Discard redundant graphics operations", depending on which version of Presentation Server you're running.
The Queuing & Tossing feature of Thinwire briefly queues GDI draw commands and, before sending them over ICA, inspects the stack in reverse order (LIFO) to allow tossing of obsolete commands (those which have been overwritten by subsequent commands). The queuing period is short enough (30ms) that it doesn't degrade the responsiveness of the application; in fact, performance is significantly improved because draw commands that are logically redundant are discarded.
The tossing algorithm was enhanced in Presentation Server 4.5 (Ohio) to look for more graphics constructs. The tossing algorithm now uses a 1-bit-per-pixel map of the session screen. And it can detect complete self-contained 'frames'. As a result, Thinwire will either send the entire frame to the client as a self-contained entity or toss it completely. These improvements to the tossing algorithm further reduce the amount of data that needs to be sent over the wire. Along with reduced network bandwidth consumption, network efficiency (data bytes per frame) is increased. And the user experience is better because the entire frame gets updated at once rather than in pieces.
So, just how big a difference does all of this make? I recently spoke with one of our engineers who has been taking performance measurements with Flash videos. In his testing, he found that enabling Queuing & Tossing reduced bandwidth consumption by more than 3 times!
In addition to the new framing behavior of Queuing & Tossing in PS 4.5, just-in-time output behavior has further improved Flash performance. Flash video playback with PS 4.5 is noticeably smoother. And CPU consumption is lower, which increases server scalability (number of simultaneous Flash users per server).
There's still quite a bit more to tell you about Adobe Flash performance optimization, so stay tuned for my next installment on this topic.
Derek Thorslund
Product Strategist, Multimedia Virtualization
Comments (5)
Dec 14, 2007
Anonymous says:
Awesome material coming from you Derek. Keep up the great work. ShawnAwesome material coming from you Derek. Keep up the great work.
Shawn
Feb 01, 2008
Ryon Brubaker says:
Derek, where is fix for those using W2K and CPS 4.0? As you said...Flash 7...Derek, where is fix for those using W2K and CPS 4.0? As you said...Flash 7 is only truly supported version on 4.0, 9 is out.
Thanks.
Feb 12, 2008
Derek Thorslund says:
There's a Knowledge Base article at http://kb.citrite.net/article/ctx115426...There's a Knowledge Base article at http://kb.citrite.net/article/ctx115426 that describes a currently available hotfix (PSE400R03W2K3091) for Presentation Server 4.0 for Windows Server 2003 to support SpeedScreen Flash Acceleration for Adobe Flash versions 7a, 8, 8b, 9, 9c and 9d. If you need anything else, please open a case with Citrix Support so that they can address your needs.
Mar 09, 2008
Anonymous says:
First of all...I asked about Windows 2000 server, not 2003. Not sure why I...First of all...I asked about Windows 2000 server, not 2003. Not sure why I got the "pass the buck" response. Either there is a fix or not. You work for Citrix, can't you just ask/email/call/IM someone there? Plus the article you mention (Even if I had 2003 server, which AGAIN I don't) does not exist either does the previous link in part 1&2 in your blog.. after you logon to MyCitrix. Maybe you might want to fix your Blog, not a reliable source.
Should I update the thread on the support forums with your response? At this point SpeedScreen is SpeedCrapola.
http://support.citrix.com/forums/thread.jspa?forumID=75&threadID=98763&tstart=0
Next time I "need anything else"...won't look here. Sorry I wasted your time and mine.
Mar 20, 2008
Derek Thorslund says:
Ouch, Ryon, that stings. But thanks for letting me know about the problem you ar...Ouch, Ryon, that stings. But thanks for letting me know about the problem you are having accessing KB article 115426. I have now learned that there are access controls on KB articles for limited release hotfixes. Hotfixes are often first released on a limited basis only to customers with active Preferred Support Services contracts before they are made more widely available. Greg Anth, who is on the Citrix Knowledge Center team, commented on my previous blog post about the Flash hotfix: "Limited Release Hotfix articles are only available to customers with approved support contracts. For a list of support programs, please visit:
http://citrix.com/English/ss/supportSecond.asp?slID=25635." If you are unable to obtain the article from Support, give me a call at '954-267-3000' or send me an email and I will look after you.
When I wrote my first blog post on optimizing Flash performance and when I replied to your first comment above, we had a hotfix available for PS 4.0 for Windows Server 2003 but not for Windows Server 2000. As I noted, the process to request a new hotfix is to open a ticket with Support. They monitor such customer requests and work with our Life Cycle Maintenance (LCM) team to prioritize hotfix development to address the needs of our customers. I'm pleased to report that the process works. Evidently some other customers opened tickets to request a hotfix for PS 4.0 for Windows Server 2000. And so another hotfix has been created and it is now available to customers with approved support contracts. I'll provide the details in a new blog post momentarily, and include an update on other developments around SpeedScreen Flash Acceleration.
Derek
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