Profiling maps

So I'm making a detailed map and I found that 1 place in a map causes big fps drop. First I thought it's just because of complex geometry but then I've added another area which also has lots of details but doesn't lag. How can I profile the map to see what's causing the performance drop? Source engine has a +showbudget command which pops up a nice GUI that tells exact timing of each subsystem call.
In my case it looks like the glass seems to be the cause but I'm not sure.
In my case it looks like the glass seems to be the cause but I'm not sure.