Observation on Hadrian's relative performance re current buildsystem

Malcolm Wallace malcolm.wallace at me.com
Sat Nov 18 11:09:28 UTC 2017


On 17 Nov 2017, at 18:46, Ben Gamari wrote:

> Simon Peyton Jones via ghc-devs <ghc-devs at haskell.org> writes:
> 
>> Urk! I expected Hadrian to be faster because it has more accurate dependencies. 
>> 
> While this is just speculation, this might actually be one of the
> reasons why the no-op case is slower: in make's case the dependency
> graph is mostly static whereas in Hadrian the build system needs to
> discover dependencies dynamically.
> 
> Either way, thanks for this characterization, Herbert!


But surely the timing for a full build from scratch is not the most important thing to compare?  In my work environment, full builds are extremely rare; the common case is an incremental build after pulling changes from upstream.  Is this something you can measure? 

Regards,
    Malcolm



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