Changes between Version 12 and Version 13 of Commentary/Profiling


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Timestamp:
Feb 7, 2007 8:28:49 AM (9 years ago)
Author:
kirsten
Comment:

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  • Commentary/Profiling

    v12 v13  
    11= Profiling =
    22
    3 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.
     3GHC includes at least two types of profiling: cost-centre profiling and ticky-ticky profiling.
    44
    55Cost-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.
     
    1313== Ticky-ticky profiling ==
    1414
    15 The code for this isn't in the HEAD yet. Should be checked in soon.
     15Ticky-ticky should now be working in the HEAD, though not in any so-far-released version.
    1616
    1717TODO: update the GHC manual section on this.