I can't even see what performance number has changed, because harbourmaster only shows the tail of the log.
From https://phabricator.haskell.org/harbormaster/build/4553:
10 bytes allocated value is too high: 11 Expected haddock.Cabal(normal) bytes allocated: 6710234312 +/-5% 12 Lower bound haddock.Cabal(normal) bytes allocated: 6374722596 13 Upper bound haddock.Cabal(normal) bytes allocated: 7045746028 14 Actual haddock.Cabal(normal) bytes allocated: 7417348832 15 Deviation haddock.Cabal(normal) bytes allocated: 10.5 % 16 *** unexpected stat test failure for haddock.Cabal(normal) 17 bytes allocated value is too high: 18 Expected haddock.compiler(normal) bytes allocated: 36740649320 +/-10% 19 Lower bound haddock.compiler(normal) bytes allocated: 33066584388 20 Upper bound haddock.compiler(normal) bytes allocated: 40414714252 21 Actual haddock.compiler(normal) bytes allocated: 40681382656 22 Deviation haddock.compiler(normal) bytes allocated: 10.7 % 23 *** unexpected stat test failure for haddock.compiler(normal)