Perf on T10858

Ben Gamari ben at
Thu Oct 20 14:20:42 UTC 2016

Simon Peyton Jones via ghc-devs <ghc-devs at> writes:

> I’m getting this on HEAD on my Linux box (64 bit)
> cd "./perf/" &&  "/5playpen/simonpj/HEAD-2/inplace/test   spaces/ghc-stage2" -c T10858.hs -dcore-lint -dcmm-lint -no-user-package-db -rtsopts -fno-warn-missed-specialisations -fshow-warning-groups -dno-debug-output  -O +RTS -V0 -tT10858.comp.stats --machine-readable -RTS
> bytes allocated value is too low:
> (If this is because you have improved GHC, please
> update the test so that GHC doesn't regress again)
>     Expected    T10858(normal) bytes allocated: 241655120 +/-8%
>     Lower bound T10858(normal) bytes allocated: 222322710
>     Upper bound T10858(normal) bytes allocated: 260987530
>     Actual      T10858(normal) bytes allocated: 221938928
>     Deviation   T10858(normal) bytes allocated:      -8.2 %
> Does anyone else?  It’s good – but why isn’t Harbormaster complaining?
A very good question. It looks like the result is straddling the edge of
acceptable so it's conceivable that Harbormaster is (for some reason)
just below the failing threshold. We've seen this sort of small
non-determinism in allocations in the past, although I don't have a
compelling explanation for why.


- Ben
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