Build resilient systems at scale
28–30 October 2015 • Amsterdam, The Netherlands

Forensic tools for in-depth performance investigation

Philip Tellis (Akamai), Nic Jansma (Akamai)
14:00–15:30 Wednesday, 28/10/2015
Location: G102/103
Average rating: ****.
(4.06, 47 ratings)
Slides:   1-PDF 

Prerequisite Knowledge

While this is an advanced level talk, there is no particular pre-requisite knowledge that we won't cover if necessary. Intermediate audiences might also find it useful.


We are a third-party script provider, and we work with a lot of customers across various verticals. One of our customers in the retail space recently noticed that a particular page had performance problems, that on the face of it pointed to our script as the cause. This confused us because of the non-blocking/SPOFing nature of our script, but we take these performance complaints seriously, so we started our investigation to find the root cause of the problem.

We went through a series of tools including our own RUM based waterfalls, Webpagetest, and packet captures to study the problem.

In this talk we’ll run through our analysis and see how the potential cause of a problem can change drastically as you look deeper.

Photo of Philip Tellis

Philip Tellis


Philip Tellis is a geek who likes to make the computer do his work for him. As principal RUM distiller at Akamai, he analyses the impact of various design decisions on web-application performance, scalability, and security. He is the lead developer of boomerang—a JavaScript-based web-performance testing tool. Philip has spoken at several conferences in the past, including FOSS.IN, FREED.IN, Ubuntulive, Linux Symposium, OpenSource Bridge, PHP Quebec, ConFoo, FOSDEM, IPC, WebDU, Velocity and JSConf. He writes for Smashing Magazine and blogs at The Other Side of the Moon. In his spare time, Philip enjoys cycling, reading, cooking, and learning spoken languages.

Photo of Nic Jansma

Nic Jansma


Nic Jansma is a software developer at Akamai building high-performance websites, apps, and open source tools.