[sokoloff]

1. Yes, but if you use a representative size dataset and the profiler doesn't show that as a hotspot, there's no point in changing algorithms.

2. Agreed, but remember the value of the profiler is telling you, "You're spending 97% of your time in this small subset of your code" and your job is to conclude, "Hmm, I should look there for improvements and not at the whole rest of the program." It can't tell you what changes to make, but it keeps you from spending time optimizing what's in the 3% of runtime.

3. Agreed, with the caveat that most profilers that I've used did tell me the absolute overall slowness in addition to the relative slowness, but that wasn't the major thrust of your comment so I'll just observe that small difference and otherwise agree.