I asked the same question not too long ago
I’ve downloaded and tried AQtime. It does seem comprehensive, but it is not an easy to use tool and is VERY expensive for an individual programmer (i.e. $600 US). I loved the fact that it was non-invasive (did not change your code), and that it could do line-by-line profiling, until I found that because it is an instrumenting profiler, it can lead to improper optimizations as in: Why is CharInSet faster than Case statement?
I tried a demo of ProDelphi, much less expensive (about $80 I think), but it was much too clunky for me – I didn’t like the user interface at all, and it is invasive – changing your code to add the instrumenting, which you have to be careful about.
I used GpProfile with Delphi 4 for many years. I loved it. It also was invasive, but it worked so well I learned to trust it and it never gave me a problem in 10 years. But when I upgraded to Delphi 2009, I didn’t think it best to try using it, since it hasn’t been upgraded and by GP’s admission, won’t work without modifications. I expect you won’t be able to use it either with Delphi 2006.
ProDelphi and GpProfile will only profile at the procedure level. If you want to do individual lines (which I sometimes had to), you have to call PROC1, PROC2, PROC3 for each line and put the one line in each PROC. It was a bit of an annoyance to have to do that, but it gave me good results (at least I was happy with the results of GpProfile doing that).
The answer I accepted in my CharInSet question said that “Sampling profilers, which periodically check the location of the CPU, are usually better for measuring code time.” and a later answer gave Eric Grange’s free sampling profiler for Delphi that now supports Delphi 2009. I haven’t tried it yet, but I’ve heard good things about it, and it is the next one I’m going to try.
By the way, you might be best off by saving your $600 by NOT buying AQtime, and instead using that to upgrade your Delphi 2006 to Delphi 2009. The stability, speed and extra features (expecially Unicode), will be worth your while. See: What are major incentives to upgrade to D2009 (Unicode excluded)?
Also AQtime does not integrate into Delphi 2009 yet.
One other free one, with source that I found out about, but haven’t tried yet is TProfiler. If anyone has tried that one, I’d like to know what they think.
Note: The Addenum I added afterwards to question 291631 seems like it may be the answer. See Andre’s open source program: asmprofiler
Feb 2010 followup. I bit the bullet and purchased AQTime. A few months ago they finally integrated it into Delphi 2009 which is what I use (but they still have to do Delphi 2010). The viewing of source lines and their individual times and counts is invaluable to me, and AQTime does a superb job of this.