https://github.com/codedownio/time-ghc-modules
Analyze GHC .dump-timings files
https://github.com/codedownio/time-ghc-modules
Last synced: 10 months ago
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Analyze GHC .dump-timings files
- Host: GitHub
- URL: https://github.com/codedownio/time-ghc-modules
- Owner: codedownio
- License: mit
- Created: 2021-07-31T00:16:15.000Z (almost 5 years ago)
- Default Branch: master
- Last Pushed: 2024-02-14T05:29:47.000Z (over 2 years ago)
- Last Synced: 2025-05-19T02:12:35.896Z (about 1 year ago)
- Language: HTML
- Homepage:
- Size: 6.47 MB
- Stars: 106
- Watchers: 4
- Forks: 4
- Open Issues: 1
-
Metadata Files:
- Readme: README.md
- Changelog: CHANGELOG.md
- License: LICENSE
Awesome Lists containing this project
README
# time-ghc-modules
Figure out why your builds are slow. This tool analyzes how long it takes GHC to compile your Haskell modules, broken down by phase. It can draw both bar charts and treemaps, of time or space usage.
# Quick start
``` shell
cd
stack clean
stack build --ghc-options "-ddump-to-file -ddump-timings"
# ----- OR -----
cabal clean
cabal build all --ghc-options "-ddump-to-file -ddump-timings"
```
If you have Nix, you can simply run `time-ghc-modules` from Nixpkgs!
``` shell
nix run nixpkgs#time-ghc-modules
```
Or, clone the repo first:
``` shell
git clone git@github.com:codedownio/time-ghc-modules.git /path/to/time-ghc-modules
# If you have Nix, you can use the fully reproducible version
/path/to/time-ghc-modules/time-ghc-modules-nix
# Otherwise, your system needs to have SQLite >= 3.33.0, Python 3, and sed
/path/to/time-ghc-modules/time-ghc-modules
```
The script will search for all your `*.dump-timings` files and analyze them. It will finish by printing out the path to an HTML file:
``` shell
...
--> Wrote report at file:///tmp/tmp.pvnp4FYmLa/report.html
```
# Example: hledger
You can generate the time report below for [hledger](https://github.com/simonmichael/hledger) by running the following commands (assuming you have Nix).
``` shell
set -e
cd $(mktemp -d)
git clone git@github.com:simonmichael/hledger.git
git clone git@github.com:codedownio/time-ghc-modules.git
cd hledger
stack build --ghc-options "-ddump-to-file -ddump-timings"
../time-ghc-modules/time-ghc-modules-nix
```
# Tips
* The script will output its log messages to `stderr` and print the final report path to `stdout` (assuming it didn't exit with a failure). This makes it easy to use the output in scripts. For example:
``` shell
# Build the report and open it in your browser
> firefox $(/path/to/time-ghc-modules/time-ghc-modules)
```
``` shell
# Build the report in CI and stash it somewhere
> cp $(/path/to/time-ghc-modules/time-ghc-modules) $MY_CI_ARTIFACTS_DIR/
```
* You can also look at the timing of individual components, but doing e.g. `stack build some-component:lib`. But, make sure to clean up any old `.dump-timings` files from previous runs:
``` shell
find . -name "*.dump-timings" | xargs rm
```
* GHC's `-dumpdir` option can be used to consolidate the `.dump-timings` files, so they aren't left all over your source tree. For example:
``` shell
stack build --ghc-options "-ddump-to-file -ddump-timings -dumpdir .ghcdump"
```
# Compatibility
The flag `-ddump-timings` is available for `GHC >= 8.4.1`.