I’m getting this on HEAD on my Linux box (64 bit) cd "./perf/T10858.run" && "/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? Simon