High CPU usage with ASPX sample page

Jul 17, 2009 at 7:18 PM
Edited Jul 17, 2009 at 7:23 PM

While trying to figure out why an application we have has constant CPU usage around 40% only when the map is displayed (i.e. the app has tabs, the map is on one of them), I decided to build an empty website with nothing but DeepEarth in it. What I found is a bit puzzling.

As you know, when you add a Silverilght application to a website it creates two test pages. One HTML using the object tag and one ASPX using the ASP.NET Silverlight control. With nothing but the DeepEarth map in the Silverlight app, the HTML page settles at 0% CPU after the initial load while the ASPX page remains at 20-30%.

Has anyone else noticed this? Note that, for me, this happens with IE8 and not FF3.

I'll open a ticket and attach the sample project if someone is interested in looking at it.

Edit: Here's a link to the project files http://deepearth.codeplex.com/WorkItem/View.aspx?WorkItemId=4603

Jul 17, 2009 at 9:56 PM

I'll take a look, I use Silverlight Spy to see the actual cpu and memory usage from the silverlight app. The application should consume a bunch of CPU onload as it streams in the tiles, then goto 0% if your mouse is not moving. 

I've been having issues in the last few days with a Windows update process kicking off when i run the application and killing my CPU - 100%. This maybe unrelated however.

FYI: In Silverlight3 they have dropped the aspx control, everything will use the HTML object syntax.

Jul 21, 2009 at 12:05 PM
Edited Jul 22, 2009 at 11:22 AM

I have had the issue for months.  It also happens with the Silverlight Map Control, so it isnt a Deep Earth thing.

It happens in I.E. but not other browsers.

But the good news is that it is gone in Silverlight 3.  I have not seen it since moving to the Release silveright 3 version.

If you have access to the MSDN Connect sharepoint site for the Silverlight Map Control, in the Issues List, there are at least 2 entries for this.  One titled "cpu usage increases 25-50%" and another that just showed up saying that they are seeing something similar with Silverlight 3  "High CPU when adding a layer".  So they know about it, they just havent commented publicly about it.