Re: GHC build time graphs

On 01/28/16 11:34 PM, Ben Gamari wrote:

Joachim Breitner writes:

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Hi Oleg,

Am Freitag, den 29.01.2016, 00:22 +0200 schrieb Oleg Grenrus:

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Is the same compiler used to build HEAD and 7.10,1?

Good call. In fact, no: 7.10.1 is built with 7.6.3, while HEAD is built with 7.10.3.

Anthony’s link, i.e. https://perf.haskell.org/ghc/#compare/ca00def1d7093d6b5b2a937ddfc8a01c152038... has links to the build logs of either build; there I could find that information.

That might be (part) of the problem. But if it is, it is even worse, as it would mean not only building the compiler got slower, but the compiler itself...

I can verify that the build itself is indeed slower. Validating the current state of ghc-7.10 takes 19 minutes, whereas ghc-8.0 takes 25.5 minutes. This isn't entirely unexpected but the change is quite a bit larger than I had thought. It would be nice to know which commits are responsible.

btw, just recent experience on ARM64 (X-gene board): bootstrapping 7.10.1 with 7.6.x took: ~120 minutes bootstrapping 8.0.1 RC2 with 7.10.1 took: ~446 minutes both run as: ./configure; time make -j8 although board is shared I've tried to look at it from time to time and have not observed anyone else there so I can assume this is indeed GHC slowness on unregisterised -fvia-C ports... Karel