#15703: Significant compilation time blowup when refactoring singletons-heavy code -------------------------------------+------------------------------------- Reporter: RyanGlScott | Owner: (none) Type: bug | Status: new Priority: normal | Milestone: 8.8.1 Component: Compiler | Version: 8.6.1 Resolution: | Keywords: Operating System: Unknown/Multiple | Architecture: Type of failure: Compile-time | Unknown/Multiple performance bug | Test Case: Blocked By: | Blocking: Related Tickets: | Differential Rev(s): Wiki Page: | -------------------------------------+------------------------------------- Comment (by RyanGlScott): I added `{-# OPTIONS_GHC -fprof-auto #-}` to the top of `OptCoercion`, which gives me some slightly more fine-grained information: {{{ Mon Oct 8 13:50 2018 Time and Allocation Profiling Report (Final) ghc-stage2 +RTS -p -RTS -B/u/rgscott/Software/ghc3/inplace/lib -O1 -fforce-recomp Lib.hs total time = 282.87 secs (282872 ticks @ 1000 us, 1 processor) total alloc = 403,927,138,248 bytes (excludes profiling overheads) COST CENTRE MODULE SRC %time %alloc matchAxiom OptCoercion compiler/types/OptCoercion.hs:(903,1)-(916,11) 47.3 43.4 substTyWith TyCoRep compiler/types/TyCoRep.hs:(2213,23)-(2214,50) 23.0 22.9 opt_trans_rule OptCoercion compiler/types/OptCoercion.hs:(512,1)-(681,30) 18.4 21.5 etaAppCo_maybe OptCoercion compiler/types/OptCoercion.hs:(985,1)-(996,11) 6.1 9.2 opt_co4 OptCoercion compiler/types/OptCoercion.hs:(174,1)-(386,71) 3.4 2.2 }}} -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/15703#comment:5 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler