Ben Livshits, Microsoft Research

Addressing Web 2.0 Application Development Challenges


Abstract:

With all the hype surrounding Web 2.0, developing distributed web
applications is an experience that leaves much to be desired. This
talk focuses on two recent projects that address Web 2.0 application
development challenges.

AjaxScope recently publicly released by Microsoft Research is a
monitoring platform for Web 2.0 application such as Live Maps and
Gmail within the end-user browser. AjaxScope allows for a wide variety
of instrumentation policies that allow the developer to gain insight
into the behavior of remotely executing code. We have developed and
experimented with a wide range of runtime monitoring policies for
performance profiling, locating optimization opportunities, finding
bugs such as memory leaks, etc. The fact that AjaxScope is deployed in
a distributed setting allows us to distribute the instrumentation
across a range of users and adopt it over time, so as to keep the
per-user instrumentation overhead as low as possible.

Doloto is an automatic code rewriting tool that improves the
responsiveness of large web applications through automatic splitting
of JavaScript code. While moving application code to the client
browser improves user-perceived performance during program execution,
the downside is that a great deal of can execute. Doloto analyzes web
application workloads to automatically split them into a small initial
download and multiple dynamic libraries loaded lazily or on-demand. We
have applied Doloto to several large web applications. Doloto reduces
the size of initial application code download by hundreds of kilobytes
or as much as 50% of the original download size. The time to download
and begin interacting with large applications is reduced by 20-40%
depending on the wide-area network conditions.