Note that Travis CI time is a sum of all operations, including fetching/saving caches etc.
Opening the build log and looking for the compilation might be more revealing. For example, 7.10 seems ~10 seconds, 8.2.1 seems ~50 seconds. There are two issues I can see with this, that should be addressed by benchmarking: 1) The Travis CI build hosts might show varying performance across reruns due to shared machines. 2) Tuning the RTS params when invoking GHC as a compiler can yield significant benefits, at least on larger compilations (such as -A128m). It would probably be doable to fetch a set of packages from *ackage and build with various compilers under controlled circumstances? Robin 2017-07-04 9:16 GMT+02:00 Deest, Gaël <[email protected]>: > Hi all, > > As you are probably well aware, GHC performance has been a growing concern > over the last few years. Many Haskell programmers complain that build time > has significantly increased over the last few releases. However, to our > knowledge, there isn't much data available to substantiate this claim and > the severity of these problems is not well known. > > That's why we would like to bring some anecdotal evidence to your > attention that seems to indicate really major performance regressions. We > stumbled upon the CI of the data-reify package, which is built against all > GHC releases since 2010 : > > https://travis-ci.org/ku-fpg/data-reify > > tl;dr: Build time has gone from 1 min 32s for GHC 7.0 to 4 min 35s for GHC > 8.2. The 8.2 release alone seems to have increased compilation time by > almost 2 minutes, with the current development branch bringing only minor > performance improvements. > > Of course, this single data point is not sufficient to establish how > severe and widespread these problems are. More data could probably be > gathered from other packages. However, it certainly matches our > (subjective) experience and we felt important to report it to you. > > Regards, > > -- > Gaël Deest > Tweag I/O > > _______________________________________________ > ghc-devs mailing list > [email protected] > http://mail.haskell.org/cgi-bin/mailman/listinfo/ghc-devs > >
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