Performance Blog

Tools for Web Performance Analysis

Posted on: January 21, 2011

At Yahoo!, I’m currently focused on analysis of end user performance. This is a little different than what I’ve worked on in the past, which was mainly server-side performance and scalability. The new focus requires a new list of tools so I thought I’d use this post to share the tools I’ve been learning and using in the past couple of months.


This made the top of my list and I use it almost every day. Although it has features very similar to firebug, it has two features that I find very useful – the ability to save the waterfall data directly to a csv file and a stand-alone HttpWatch Studio tool that easily loads previously saved data and reconstructs the waterfall ( I know you can export Net data from firebug, but only in HAR format). And best of all, HttpWatch works with both IE and Firefox. The downside is that it works only on Windows and it’s not free.


This is everyone’s favorite tool and I love it too. Great for debugging as well as performance analysis. It is a little buggy though – I get frustrated when after starting Firebug, I go to a URL expecting it to capture my requests, only to find that it disappears on me. I end up keeping firebug on all the time and this can get annoying.


This is also a Windows-only commercial tool – it is similar to Wireshark. It’s primary focus is http however, so it is easier to use than Wireshark. Since it sits at the OS level, it captures all traffic, irrespective of which browser or application is making the http request. As such, it’s a great tool for analyzing non-browser based http client applications.


Yet another commercial tool, but considering our global presence and the dozens of websites that need to  be tested from different locations, we need a robust, commercial tool that can meet our synthetic testing and monitoring requirements. Gomez has pretty good coverage across the world.

I have a love-hate relationship with Gomez. I love the fact that I can do the testing I want at both backbone and  last mile, but I hate it’s user interface and limited data visualization. We have to resort to extracting the data using web services and do the analysis and visualization ourselves. I really can’t complain too much – since I didn’t have to build these tools myself !

Command-line tools

Last, but not the least, I rely heavily on standard Unix command-line tools like nslookup, DIG, curl, ifconfig, netstat, etc. And my favorite text processing tools remain sed and awk. Every time I say that, people shake their heads or roll their eyes. But we can agree to dis-agree without getting into language wars I think.


4 Responses to "Tools for Web Performance Analysis"

[…] This post was mentioned on Twitter by adrian cockcroft, Shanti Subramanyam. Shanti Subramanyam said: Just published blog post on the performance tools I have been using recently at […]

Hi Shanti.

Nice to see you blogging again. I have been reading your blogs and they are quite a good source of info.

I am very much interested in how do you measure the rendering time in Yahoo, because of so many different apps and APIs


Thanks Krishna – you motivate me to be more regular about my blogging now. Measuring the rendering time is indeed hard, requiring custom code and post-processing but are you sure that’s your problem? Even for a complex page like, the rendering time is < 15% of the total response time (See slide 67 of Nicholas Zakas' excellent presentation:

Have a look at Fiddler for analysing web traffic, extremely powerful and best of all free!

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