I really enjoyed this talk and thought it was a great introduction into xhprof with convincing explanations as to why you should use profiling talks instead of naive profiling.
I'd note that the slides were a bit hard to read at times due to the colour scheme of the screenshots taken from XHProf, but this was exaggerated by the use of an LCD screen instead of a larger projector due to the venue. I also think a really nice thing that could be covered is when you should be profiling your applications (in production, whilst you are developing [continuous profiling] or at some point in the future after you've deployed a new feature).
A really important topic, thanks for discussing it so eloquently and encouraging more people to understand it
Excellent talk about a delicate subject which needs to be promoted in the developer community. Good to see you doing this.
A good talk on an important topic that rings true with many in our industry.