|Version 9 (modified by kirsten, 9 years ago) (diff)|
GHC includes at least two types of profiling: cost-centre profiling and ticky-ticky profiling. Ticky-ticky profiling is currently not working in the HEAD, but hopefully should be working again soon.
Cost-centre profiling operates at something close to the source level, and ticky-ticky profiling operates at something much closer to the machine level. This means that the two types of profiling are useful for different tasks. Ticky-ticky profiling is mainly meant for compiler implementors, and cost-centre profiling for mortals. However, because cost-centre profiling operates at a high level, it can be difficult (if not impossible) to use it to profile optimized code. Personally, I (Kirsten) have had a lot of success using cost-centre profiling to find problems that were due to my own bad algorithms, but less success once I was fairly sure that I wasn't doing anything obviously stupid and was trying to figure out why my code didn't get optimized as well as it could have been.
(add more details)
(The following are my notes as I try to get this working again. Once it is working, I'll turn it into something more coherent. -krc)