Ben Gamari <ben@smart-cactus.org> writes: snip
The "normal" and "profiled" build metrics are the +RTS -t lines extract from Cabal's profiled and unprofiled GHC invocations. I believe the RTS timings for 8.0.2 are broken due to a (fixed) RTS bug, although I can't come up with a reference at the moment.
I tried this again with regex-tdfa-1.2.2 and indeed I was able to reproduce Herbert's result, 8.0.2 normal: <<ghc: 91199006664 bytes, 3573 GCs, 260839393/610327968 avg/max bytes residency (30 samples), 1687M in use, 0.000 INIT (0.001 elapsed), 0.319 MUT (49.441 elapsed), 0.858 GC (30.681 elapsed) :ghc>> profiled: <<ghc: 73210356144 bytes, 3333 GCs, 225266643/599801320 avg/max bytes residency (26 samples), 1731M in use, 0.000 INIT (0.001 elapsed), 0.352 MUT (39.318 elapsed), 0.685 GC (21.644 elapsed) :ghc>> 8.2.1-rc2: normal: <<ghc: 90928069104 bytes, 3655 GCs, 256129517/594585536 avg/max bytes residency (29 samples), 1691M in use, 0.000 INIT (0.001 elapsed), 1.137 MUT (84.652 elapsed), 0.941 GC (47.811 elapsed) :ghc>> profiled: <<ghc: 73010065480 bytes, 3228 GCs, 225992177/578697488 avg/max bytes residency (27 samples), 1649M in use, 0.000 INIT (0.001 elapsed), 0.318 MUT (53.871 elapsed), 0.728 GC (32.681 elapsed) :ghc>> We'll need to look at what is going on here as this is a pretty significant regression. Cheers, - Ben