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

Joachim Breitner <mail@joachim-breitner.de> writes:

Hi Oleg,

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

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/ca00def1d7093d6b5b2a937ddfc8a01c152038eb/a496f82d5684f3025a60877600e82f0b29736e85
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