[GHC] #13566: Bigger core size in ghc8 compared to ghc7
#13566: Bigger core size in ghc8 compared to ghc7 -------------------------------------+------------------------------------- Reporter: pacak | Owner: (none) Type: bug | Status: new Priority: normal | Milestone: Component: Compiler | Version: 8.2.1-rc2 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: -------------------------------------+------------------------------------- Generated core size (as reported by ghc -v) is much bigger in ghc 8.0.2 compared to ghc 7.10.1. Things are slightly better in ghc 8.2.0rc2, but not as good as in ghc7 I think that results in a slight runtime performance problem. steps to reproduce: ghc -O A.hs {{{ Result size of CorePrep = {terms: 5,016, types: 9,813, coercions: 1,443} -- ghc8 Result size of CorePrep = {terms: 975, types: 2,375, coercions: 150} -- ghc7 Result size of CorePrep = {terms: 1,342, types: 2,838, coercions: 320, joins: 0/66} -- ghc8.2 }}} -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/13566 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler
#13566: Bigger core size in ghc8 compared to ghc7 -------------------------------------+------------------------------------- Reporter: pacak | Owner: (none) Type: bug | Status: new Priority: normal | Milestone: Component: Compiler | Version: 8.2.1-rc2 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: | -------------------------------------+------------------------------------- Changes (by pacak): * Attachment "sample.zip" added. -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/13566 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler
#13566: Bigger core size in ghc8 compared to ghc7 -------------------------------------+------------------------------------- Reporter: pacak | Owner: (none) Type: bug | Status: new Priority: normal | Milestone: Component: Compiler | Version: 8.2.1-rc2 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: | -------------------------------------+------------------------------------- Changes (by pacak): * Attachment "sample.zip" added. (right sample) -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/13566 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler
#13566: Bigger core size in ghc8 compared to ghc7 -------------------------------------+------------------------------------- Reporter: pacak | Owner: (none) Type: bug | Status: new Priority: normal | Milestone: Component: Compiler | Version: 8.2.1-rc2 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 pacak): If you comment out {{{ {-# SPECIALISE instance AdditiveGroup (Piecewise IntOfLogPoly4 Double) #-} }}} in Numeric/Polynomial/Piecewise.hs ghc7 version starts behaving similar to ghc8, at the same time AdditiveGroup instance is not used at all anywhere. -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/13566#comment:1 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler
#13566: Bigger core size in ghc8 compared to ghc7 -------------------------------------+------------------------------------- Reporter: pacak | Owner: (none) Type: bug | Status: new Priority: normal | Milestone: Component: Compiler | Version: 8.2.1-rc2 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 mpickering): pacak also says on IRC that inlining any of the three files into each other leads to smaller core. Also the `INLINE` and `INLINABLE` pragmas are necessary in `A.hs`. -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/13566#comment:2 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler
#13566: Bigger core size in ghc8 compared to ghc7 -------------------------------------+------------------------------------- Reporter: pacak | Owner: (none) Type: bug | Status: new Priority: normal | Milestone: Component: Compiler | Version: 8.2.1-rc2 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 rwbarton): This reproducer depends on vector. What version? With vector-0.11.0.0 and ghc-8.0.1 I got these numbers: {{{ Result size of CorePrep = {terms: 1,227, types: 2,667, coercions: 256} }}} -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/13566#comment:3 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler
#13566: Bigger core size in ghc8 compared to ghc7 -------------------------------------+------------------------------------- Reporter: pacak | Owner: (none) Type: bug | Status: new Priority: normal | Milestone: Component: Compiler | Version: 8.2.1-rc2 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 pacak): I was able to reproduce this vector-0.10.12.3 for ghc7 and ghc8 and with vector-0.12.0.1 -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/13566#comment:4 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler
#13566: Bigger core size in ghc8 compared to ghc7 -------------------------------------+------------------------------------- Reporter: pacak | Owner: (none) Type: bug | Status: new Priority: normal | Milestone: Component: Compiler | Version: 8.2.1-rc2 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): From 975 in GHC 7.10 to 1,342 in GHC 8.2 doesn't sound terrible. -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/13566#comment:5 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler
#13566: Bigger core size in ghc8 compared to ghc7 -------------------------------------+------------------------------------- Reporter: pacak | Owner: (none) Type: bug | Status: new Priority: normal | Milestone: Component: Compiler | Version: 8.2.1-rc2 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 pacak):
From 975 in GHC 7.10 to 1,342 in GHC 8.2 doesn't sound terrible.
When I was stripping down the example I was looking at sizes for ghc7 and ghc8. I can try to check ghc8.2 on original code, but it'll take time. -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/13566#comment:6 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler
#13566: Bigger core size in ghc8 compared to ghc7 -------------------------------------+------------------------------------- Reporter: pacak | Owner: (none) Type: bug | Status: new Priority: normal | Milestone: Component: Compiler | Version: 8.2.1-rc2 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 pacak): GHC 8.2 on original code: {{{ Result size of Demand analysis = {terms: 5,548, types: 10,236, coercions: 2,752, joins: 10/79} !!! Demand analysis [A]: finished in 198.43 milliseconds, allocated 43.533 megabytes *** CoreTidy [A]: Result size of Tidy Core = {terms: 1,150, types: 2,274, coercions: 320, joins: 0/14} !!! CoreTidy [A]: finished in 6.72 milliseconds, allocated 6.210 megabytes writeBinIface: 149 Names writeBinIface: 279 dict entries writeBinIface: 149 Names writeBinIface: 279 dict entries *** CorePrep [A]: Result size of CorePrep = {terms: 1,342, types: 2,838, coercions: 320, joins: 0/66} }}} Looks like ghc 8.2 also produces similar sized core and manages to clean it up later. -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/13566#comment:7 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler
#13566: Bigger core size in ghc8 compared to ghc7 -------------------------------------+------------------------------------- Reporter: pacak | Owner: (none) Type: bug | Status: infoneeded Priority: normal | Milestone: Component: Compiler | Version: 8.2.1-rc2 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: | -------------------------------------+------------------------------------- Changes (by bgamari): * status: new => infoneeded Comment: I'm a bit lost here. Am I to understand from comment:7 that this was an issue in GHC 8.0 that is fixed in 8.2.1-rc1? -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/13566#comment:8 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler
#13566: Bigger core size in ghc8 compared to ghc7 -------------------------------------+------------------------------------- Reporter: pacak | Owner: (none) Type: bug | Status: infoneeded Priority: normal | Milestone: Component: Compiler | Version: 8.2.1-rc2 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 pacak):
I'm a bit lost here. Am I to understand from comment:7 that this was an issue in GHC 8.0 that is fixed in 8.2.1-rc1?
It can probably be closed for now. The problem is this sample is very fragile - for example if I remove AdditiveGroup instance which is not used at all or even specialization pragma - it suddenly works as expected in ghc 8.0. There are more code using generics in our project. If I find a way to reproduce it for ghc 8.2 - I can reopen it again with new data. -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/13566#comment:9 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler
#13566: Bigger core size in ghc8 compared to ghc7 -------------------------------------+------------------------------------- Reporter: pacak | Owner: (none) Type: bug | Status: closed Priority: normal | Milestone: Component: Compiler | Version: 8.2.1-rc2 Resolution: invalid | 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: | -------------------------------------+------------------------------------- Changes (by bgamari): * status: infoneeded => closed * resolution: => invalid Comment: Alright, do let us know if you manage to get a clean reproducer. -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/13566#comment:10 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler
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