There may be a few misconceptions about what "instrumentation" is in relation to the Quest Foglight UEM solution. For those in the dark about this concept, basically instrumentation gives you the "client perspective" when measuring end-user performance and availability of your web-sites. Client-side perspective is important when there is a lot of "stuff" in between your end-user and the application infrastructure, such as a content delivery network (CDN) like Akamai or Limewire. Since your appliance-based monitoring from Foglight lives in YOUR infrastructure not at the CDN, instrumentation can give you that "last mile" of performance information that has to be otherwise mathematically derived.
Within the Foglight family of products, our passive UEM solutions are Foglight Experience Monitor and Foglight Experience Viewer (FxM and FxV for short). These work together to analyze, measure, capture, and store each hit that goes over the wire. But not all hits go over YOUR wire when delivered by a CDN. Enter FxM Instrumentation. FxM introduced Jiffy-based client-side javascript instrumentation in version 5.5.5 but we have rewritten that code in our latest release (5.5.8) which we believe is more flexible than Jiffy. In a nutshell, we have a 40-line javascript addition that can be added to your HTML to report back to your hosted FxM and capture client-side events of performance and availability. This information captured is separated from the data we collect natively through the passive listening technology so that the reporting can be measured against each other. A new metric called "Load Time" was introduced, which is not exactly the same as "end-to-end" time. It's the time from the moment the first JavaScript executes to when the page fully loads. This type of reporting sheds light on how beneficial CDNs are to your business. If you have measured performance before and after the introduction of a CDN technology, Foglight will tell you what the performance improvement gain actually is or is not.
Instrumentation is not just limited to performance and availability customer experience (cx) metrics. FxV for instance, is in beta now with instrumentation capabilities for REPLAY of complex client-side javascript, AJAX, and other rich internet application technologies. The cx metrics around replay can be very general or quite detailed. Very detailed metrics could include a client replay that shows mouse movements, mouse clicks, delays between clicks, AJAX shopping carts being updated, etc. Again, this is not GA product yet and no target dates have been set for release, but please contact your Quest representative if interested in learning more about the coming capabilities.
With the Foglight product consistently growing in features, your end-users will soon be instruments in your orchestra of complete application performance monitoring.
--Jason
Jason Trunk is an end-user performance expert with Quest Software and can be reached on Twitter @EarlofURL