Thursday, January 31, 2008

AjaxScope Paper Provides Javascript Characterization

Emre Kıcıman and Benjamin Livshits from Microsoft Research present some interesting data in their SOPS paper - AjaxScope: A Platform for Remotely Monitoring the Client-Side Behavior of Web 2.0 Applications.

The paper is mostly about AjaxScope, a neat insturmentation and profiling tool for JavaScript.

What I want to highlight, though, are some of the measurements they present for both IE (6 and 7) as well as Firefox (2). This is real data in a refereed journal of the ACM, not a Gartner-style whitepaper.

Among the interesting nuggets are IE's 35x slower performance in String cat operations, and Firefox's 4x slower Array join execution time. The authors also put the intrinsics into context by measuring the performance of common portal pages - IE beats Firefox on, but Firefox turns the tables on Yahoo!.

Lots more interesting data, and a useful tool, in the paper. Read it.

Saturday, January 19, 2008

Web Syndication Format Market Share

For quite a while my todo list has had an instruction to find and characterize the popularity of RSS vs ATOM . Which syndication format is more popular?

Atom seems on the face of it to be a better format than RSS, but some of what it addresses are not really wide spread problems for operations. Market share will tell if it was a solution looking for a real problem or not. Atom is about 2 years old - and it is pretty common to see atom feeds available around the net now.

Measuring the breakdown among my own set of feeds that I read isn't terribly useful. I have a bias in my selections - it isn't like measuring my connectivity or transport properties where I am representative as a sample.

For the record: I have 112 feeds, 54 of them in atom and 58 in some kind of rss.

The best information I could find was from But frankly, it wasn't very satisfying. The site didn't feel very complete, and in the end only showed essentially the ratio between RSS and Atom offerings. They listed about 1/2 a million feeds - 82% of which were some flavor of RSS.

What I want to know is the ratio between active usages (i.e. fetches) of the two formats. Lots of sites offer both formats - but which do users actually consume?

Feedburner clearly has this info - but I couldn't find it published anywhere.

Does anybody have more information?

Thursday, January 17, 2008

Characterization Zealots Unite!

The eponymous Kode Vicious over at ACM's Queue magazine has an excellent rant on the value of measuring instead of assuming. I read it in print a ways back, now that it is in digital form it deserved a blog shoutout.