|
|
# Ticky-ticky profiling
|
|
|
|
|
|
|
|
|
Ticky-ticky profiling adds counters to every STG function. It's very low-level, but it really tells you what is going on:
|
|
|
|
|
|
- Add the `-ticky` flag when compiling a Haskell module to enable "ticky-ticky" profiling of that module. This makes GHC emit performance-counting instructions in every STG function.
|
|
|
|
|
|
- Add `-ticky` to the command line when linking, so that you link against a version of the runtime system that allows you to display the results.
|
|
|
|
|
|
- Add `+RTS -rfoo.ticky` to the run-time command line, to put the ticky-ticky profile in the file `foo.ticky`.
|
|
|
|
|
|
|
|
|
It's very low level stuff. You need to use `-ddump-simpl -ddump-prep` when compiling the source files to see the functions that correspond to the performance counter report.
|
|
|
|
|
|
|
|
|
You can mix modules compiled with `-ticky` and modules compiled without.
|
|
|
|
|
|
|
|
|
To really see everything you need to compile all the libraries with `-ticky`. To do that in a standard build tree, here are some flag settings in `build.mk` that work:
|
|
|
|
|
|
```wiki
|
|
|
# Build all libraries with -ticky
|
|
|
GhcLibOpts += -ticky
|
|
|
|
|
|
# Build the RTS in the ticky way
|
|
|
GhcRTSWays += t
|
|
|
|
|
|
# Currently ticky is incompatible with threading
|
|
|
GhcThreaded = NO
|
|
|
|
|
|
# When linking stage2 you need -ticky, else you get unresolved symols
|
|
|
GhcStage2HcOpts += -ticky
|
|
|
|
|
|
# Ditto Haddock
|
|
|
utils/haddock_dist_EXTRA_HC_OPTS += -ticky
|
|
|
```
|
|
|
|
|
|
|
|
|
But see [\#3439](https://gitlab.haskell.org//ghc/ghc/issues/3439), which would allow you to drop the last two. |