#8990: Performance tests behave differently depending on presence of .hi file (even with -fforce-recomp) ------------------------------------+------------------------------------- Reporter: ezyang | Owner: Type: bug | Status: new Priority: normal | Milestone: Component: Test Suite | Version: 7.9 Keywords: | Operating System: Unknown/Multiple Architecture: Unknown/Multiple | Type of failure: None/Unknown Difficulty: Unknown | Test Case: Blocked By: | Blocking: Related Tickets: | ------------------------------------+------------------------------------- Example: {{{ [ezyang@hs01 compiler]$ cat T6048.comp.stats /home/hs01/ezyang/ghc-compalloc/inplace/lib/bin/ghc-stage2 -B/home/hs01/ezyang/ghc-compalloc/inplace/lib -fforce-recomp -dno-debug- output -no-user-package-db -rtsopts -fno-ghci-history -c T6048.hs -O -fasm +RTS -V0 -tT6048.comp.stats --machine-readable [("bytes allocated", "119871672") ,("num_GCs", "100") ,("average_bytes_used", "4388904") ,("max_bytes_used", "12539576") ,("num_byte_usage_samples", "7") ,("peak_megabytes_allocated", "27") ,("init_cpu_seconds", "0.00") ,("init_wall_seconds", "0.00") ,("mutator_cpu_seconds", "0.09") ,("mutator_wall_seconds", "0.10") ,("GC_cpu_seconds", "0.15") ,("GC_wall_seconds", "0.15") ] [ezyang@hs01 compiler]$ rm T6048.hi [ezyang@hs01 compiler]$ '/home/hs01/ezyang/ghc-compalloc/inplace/bin/ghc- stage2' -fforce-recomp -dno-debug-output -no-user-package-db -rtsopts -fno-ghci-history -c T6048.hs -O -fasm +RTS -V0 -tT6048.comp.stats --machine-readable -RTS [ezyang@hs01 compiler]$ cat T6048.comp.stats /home/hs01/ezyang/ghc-compalloc/inplace/lib/bin/ghc-stage2 -B/home/hs01/ezyang/ghc-compalloc/inplace/lib -fforce-recomp -dno-debug- output -no-user-package-db -rtsopts -fno-ghci-history -c T6048.hs -O -fasm +RTS -V0 -tT6048.comp.stats --machine-readable [("bytes allocated", "121022912") ,("num_GCs", "100") ,("average_bytes_used", "4022069") ,("max_bytes_used", "11224944") ,("num_byte_usage_samples", "7") ,("peak_megabytes_allocated", "25") ,("init_cpu_seconds", "0.00") ,("init_wall_seconds", "0.00") ,("mutator_cpu_seconds", "0.09") ,("mutator_wall_seconds", "0.11") ,("GC_cpu_seconds", "0.15") ,("GC_wall_seconds", "0.14") ] }}} It's a slight but present difference: I noticed because one of the perf tests was failing on an initial run of the test suite, but passing when I re-ran it. There are two possible bugs here. One is that our implementation of `-fforce-recomp` is buggy and we shouldn't be reading in the hi file at all if `-fforce-recomp` is on; the other is that we should always clean up interface files before running one of these perf tests. -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/8990 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler