July 24, 2006

Check out the new turbo-charged Litmus!

Update: Thanks for your testing. Bug fix complete. Please resume pounding the site.

Update: Experimental site down for bug fix. Please stand by.

I've been working over the past week or so on making Litmus run under mod_perl. For those of you who aren't web applications developers (and who isn't these days? ;-), mod_perl is a technology that embeds Perl into the Apache web server. Normally, when you load a Litmus page, the web server needs to fork off a new perl process, and that process needs to spend a great deal of time loading all the required modules Litmus uses, connecting to the database, and other initialization tasks before it can even get to processing your request. Under mod_perl, all this is done exactly once--when the web server is started--and the individual child processes can focus on dealing only with requests.

Well Zach, what does this mean? The short answer is that Litmus running under mod_perl is much faster then previous versions, somewhere between 2x and 8x faster depending on how you measure.

Like everything else in this world though, there's a catch. To work under mod_perl, web applications need some degree of modification. I've been working on this for over a week now, and finally have something to show you all. If you've got a moment, pop on over to the Litmus mod_perl experimental site and give it a try. The experimental site is using a special staging copy of the database, so you can feel free to submit results or otherwise mess with it without having to worry about wasting anyone's time.

Here's what you can look out for when you're testing:


  • Anything where you're seeing content intended for someone else. Examples of this would include pages where someone else's username appears instead of your own, or where you find yourself suddenly logged in or logged out when you didn't want to be.

  • Instances where pages don't load or where you get a blank screen instead of the correct content

  • Situations where you're taken to the wrong page or something happens out of sequence. For example, you go to select a group of tests to run and are taken back to the system configuration page.

Important note: Please resist any urge you may have to run your own benchmarks on the site. The server doesn't want to handle your unnecessary load.

Again, you can check it all out at the Litmus mod_perl experimental site. Any feedback or bug reports would be much appreciated (in the comments please).

Posted by zach at July 24, 2006 5:19 PM