Heap profiling with nhc98

Heap profiling allows a programmer to see how heap space is being used within their program. This can enable space "leaks" to be identified, and their causes tracked down.

To obtain a heap profile of a computation:

  1. Compile all modules of the program with the -p option; also specify -p at link-time. Using hmake -p does all the necessary compiling and linking automatically. eg. to compile MyProg.hs and everything it depends on for heap profiling simply use hmake -p MyProg

  2. Run the program with additional runtime arguments: e.g. ./MyProg +RTS -p -RTS to output "producer" heap profile data to the file MyProg.hp

  3. Convert the raw profile data to a PostScript graph with the utility hp2graph, and view it in your favorite viewer.

Heap profiling options

-isize set the profiling interval to size (in number of allocations, or in seconds)
-p select producer profiling
-c select construction profiling
-m select per-module profiling
-r[num] select retainer profiling - num is maximum retainer set size (default=1)
-l select lifetime profiling
-b select biographical profiling
-pnames restrict profile to named producers
-cnames restrict profile to named constructions
-mnames restrict profile to named modules
-rnames restrict profile to named retainers (default=1)
-lnums restrict profile to numbered lifetimes (min-, -max, or min-max)
-bname restrict profile to named biographical phase (lag, drag, void, or use)

The first occurrence of any of the options pcmrbl determines the primary form of the profile. Subsequent pcmrbl options introduce restrictions on the profile, for instance -p -c: asks for a producer profile restricted to producers of the `:' (list) construction. Restrictions are almost all orthogonal to each other, and you may have as many as you like. Except for biography and lifetime restrictions, the format is of a list of names, separated by commas. (In general, you may need to use quotes around the list to protect special characters from the shell.)

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York Functional Programming Group