#15176: Superclass `Monad m =>` makes program run 100 times slower -------------------------------------+------------------------------------- Reporter: danilo2 | Owner: osa1 Type: bug | Status: new Priority: highest | Milestone: 8.8.1 Component: Compiler | Version: 8.4.2 Resolution: | Keywords: Operating System: Unknown/Multiple | Architecture: Type of failure: Runtime | Unknown/Multiple performance bug | Test Case: Blocked By: | Blocking: Related Tickets: | Differential Rev(s): Wiki Page: | -------------------------------------+------------------------------------- Comment (by simonpj): No no, don't do that!! Here are the big hitters in the `.ticky` files {{{ ==== Without Monad m (original.ticky) ========= 15000000 984000000 0 2 SS vx{v s21YX} (main:Main) (fun) in r1YhB 9000000 520000000 0 4 pSSS $w$dLayersFoldableBuilder__{v r1YhB} (main:Main) (fun) 24000000 320000000 0 3 SpM main:Main.$w$sgo1{v r19} (fun) 16000000 240000000 0 3 SpM main:Main.$w$sgo3{v r1a} (fun) 4000000 232000000 0 2 SS sat_s2229{v} (main:Main) (fun) in r1YhB 3000000 144000000 0 2 SS sat_s21Zw{v} (main:Main) (fun) in s21YX 9000000 72000000 0 46 ++++++++++++++++++++ luna- core-0.0.6-inplace:Luna.IR.Term.$fStorable1UniTerm10{v rihy9} (fun) 1000000 48000000 0 2 SS lvl1355{v r1Yhx} (main:Main) (fun) 2000000 32000000 0 2 SI lvl1206{v r1Yf3} (main:Main) (fun) 2000000 32000000 0 1 M luna- core-0.0.6-inplace:Luna.IR.Term.$WUniTermVar{v rihwq} (fun) 1000000 24000000 0 2 SI lvl1176{v r1Yez} (main:Main) (fun) 1000000 24000000 0 1 M luna- core-0.0.6-inplace:Luna.IR.Term.$WUniTermUnify{v rihwr} (fun) =========== With Monad m (patched.ticky) ============== 60000000 2496000000 0 7 +++++M. luna- core-0.0.6-inplace:Data.Graph.Fold.Deep.$fLayerBuilderDeepmType_$clayerBuild{v rGoW} (fun) 36000000 1584000000 0 3 >S. $s$fFunctorStateT_$cfmap{v rmuaf} (luna- core-0.0.6-inplace:OCI.Pass.Definition.Class) (fun) 24000000 1152000000 0 1 S sat_s2hor{v} (main:Main) (fun) in r2gUO 20000000 960000000 0 1 S sat_s2hqt{v} (main:Main) (fun) in r2gVh 6000000 480000000 0 3 pSS $wlvl{v r2gUO} (main:Main) (fun) 5000000 400000000 0 3 pSS $wlvl3{v r2gVh} (main:Main) (fun) 8000000 384000000 0 1 S sat_s2hoV{v} (main:Main) (fun) in r2gUQ 6000000 384000000 0 3 SSS $s$fReadertlayerm_$cread__3{v r2hmG} (main:Main) (fun) 6000000 384000000 0 3 SSS $s$fReadertlayerm_$cread__2{v r2hmw} (main:Main) (fun) 24000000 320000000 0 3 SpM main:Main.$w$sgo3{v r8e} (fun) 6000000 288000000 0 3 .SS luna- core-0.0.6-inplace:OCI.Pass.Definition.Class.$fApplicativePass5{v rmu8N} (fun) 12000000 288000000 0 2 .S lvl1{v rmual} (luna-core-0.0.6-inplace:OCI.Pass.Definition.Class) (fun) 16000000 240000000 0 3 SpM main:Main.$w$sgo1{v r8b} (fun) 2000000 160000000 0 3 pSS $wlvl1{v r2gUQ} (main:Main) (fun) 8000000 120000000 0 7 ++++++M $w$cbuild1{v riLVV} (luna-core-0.0.6-inplace:Luna.IR.Term) (fun) 9000000 96000000 0 3 SSM sat_sHlw{v} (luna-core-0.0.6-inplace:Data.Graph.Fold.Deep) (fun) in rGoW 1000000 48000000 0 2 SS lvl1702{v r2hn9} (main:Main) (fun) 2000000 32000000 0 2 SI $cpeekByteOff1{v r3Y9N} (luna-core-0.0.6-inplace:Luna.IR.Term.Core) (fun) 2000000 32000000 0 1 M luna- core-0.0.6-inplace:Luna.IR.Term.$WUniTermVar{v rihWA} (fun) 1000000 32000000 0 1 . sat_siM5u{v} (luna-core-0.0.6-inplace:Luna.IR.Term) (fun) in riLVV }}} So we are getting a log of allocation in * `luna- core-0.0.6-inplace:Data.Graph.Fold.Deep.$fLayerBuilderDeepmType_$clayerBuild` * `$s$fFunctorStateT_$cfmap{v rmuaf} (luna- core-0.0.6-inplace:OCI.Pass.Definition.Class)` Also, in the original version, the big allocation is in Main. So I'd generate `Main.stg` and the STG files for `Data.Graph.Fold.Deep, and perhaps OCI.Pass.Definition.Class.` to begin with -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/15176#comment:14 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler