Re: Initial compile time benchmarks

This ticket may be of interest: https://ghc.haskell.org/trac/ghc/ticket/9630 Deriving costs a lot and we just need someone to figure out what's going on. Edward Excerpts from Michael Sloan's message of 2016-03-29 15:23:50 -0700:

Great! Thanks for y'all putting effort towards performance. It really is crucial for developer productivity.

In the particular case of haskell-src-exts, I found that removing many of the more complicated typeclasses from deriving (Data, Generics, etc) brought the compilation time way down. IIRC it was pretty drastic, like 40 seconds vs 10 seconds (that could be just the timing for that one types module though, I don't recall). Could be valuable to investigate exactly what's going on there.

-Michael

On Tue, Mar 29, 2016 at 2:00 PM, Ömer Sinan Ağacan wrote:

...

Hi all,

Using Ben's timing patch [^1], Cabal, and a Haskell program to parse generated logs [^2], I generated some tables that show compile times of modules in hxt, haskell-src-exts, lens, and all of their dependencies:

https://gist.githubusercontent.com/osa1/fd82335181a584679c9f3200b7b0a8a5/raw...

Some notes:

- Modules and passes in modules are sorted.

- At the end of the file you can see the cumulative numbers for the passes. In fact, that's a small table so I'm just going to paste it here:

======================Total====================== CodeGen 41.32% Simplifier 34.83% Renamer/typechecker 12.22% Desugar 2.11% CorePrep 1.90% Demand analysis 1.44% CoreTidy 1.35% Called arity analysis 1.10% Float inwards 0.96% Common sub-expression 0.87% Parser 0.75% SpecConstr 0.57% Specialise 0.30% Worker Wrapper binds 0.17% Liberate case 0.12% ByteCodeGen 0.00% Simplify 0.00%

I don't know how to make use of this yet, but I thought ghc-devs may find it useful.

As a next thing I'm hoping to add some more `withTiming` calls. The analyze program can handle nested `withTiming` calls and renders passes as a tree (GHC HEAD doesn't have nested `withTiming`s so we don't see it in the file above), so we can benchmark things in more details. I also want to experiment a little bit with different `force` parameters to `withTiming`. If anyone has any other ideas I can also try those.

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[^1]: https://phabricator.haskell.org/D1959 [^2]: https://github.com/osa1/analyze-ghc-timings _______________________________________________ ghc-devs mailing list ghc-devs@haskell.org http://mail.haskell.org/cgi-bin/mailman/listinfo/ghc-devs