A great example of DevTap at work

Thanks to a recent tweet by Jason Boche I found a site on VMware Labs’ page to VMware Flings, a series of small applications VMware Labs uses internally and thought other people might find interesting. A few pieces that are already out there, like Onyx, I recognized. But the one that caught my eye was called SVGA Sonar. What does it do?

VGA Sonar is a demo application for SVGADevTap. SVGADevTap is a user-level library that communicates with the VMware SVGA guest driver to provide low-latency notifications of changes to the screen. Sonar was designed to use the devtap API to visualize application drawing patterns by rendering a scaled-down view of the desktop replacing pixel data with color-coded rectangles. As applications update the screen, Sonar presents it’s scaled version of the screen using colors to denote different types of rendering commands and whether this rendering caused a visible change to the screen. This application is called “Sonar” because the Sonar window accumulates transient updates and represents them as fading rectangles like a sonar display.

Can anyone guess what this was used for? Hint: read my previous blog post.