June 2017 - ghc-tickets

Re: [GHC] #7080: Make RULES and SPECIALISE more consistent
by GHC 27 Jun '17

27 Jun '17

#7080: Make RULES and SPECIALISE more consistent -------------------------------------+------------------------------------- Reporter: simonpj | Owner: (none) Type: bug | Status: new Priority: normal | Milestone: ⊥ Component: Compiler | Version: 7.4.2 Resolution: | Keywords: Specialise 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 simonpj): * keywords: => Specialise -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/7080#comment:3> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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Re: [GHC] #5928: INLINABLE fails to specialize in presence of simple wrapper
by GHC 27 Jun '17

27 Jun '17

#5928: INLINABLE fails to specialize in presence of simple wrapper -------------------------------------+------------------------------------- Reporter: tibbe | Owner: (none) Type: bug | Status: new Priority: normal | Milestone: Component: Compiler | Version: 7.4.1 Resolution: | Keywords: Inlining, | Specialise 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 simonpj): * keywords: Inlining => Inlining, Specialise -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/5928#comment:34> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #13701: GHCi 2x slower without -keep-tmp-files
by GHC 26 Jun '17

26 Jun '17

#13701: GHCi 2x slower without -keep-tmp-files -------------------------------------+------------------------------------- Reporter: niteria | Owner: (none) Type: task | Status: new Priority: normal | Milestone: Component: GHCi | Version: 8.3 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: -------------------------------------+------------------------------------- In D3562, I've observed that -keep-tmp-files makes :load 3x faster on my test case. I can't share my test case, but I've found a way to approximate it with `MultiLayerModules` I just added in D3575. Here are the steps: {{{ # in ghc top dir $ mkdir tmp $ cd tmp $ cp ../testsuite/tests/perf/compiler/genMultiLayerModules . # edit genMultiLayerModules to say DEPTH=0, WIDTH=5000 $ ./genMultiLayerModules $ echo ':load MultiLayerModules' | ../inplace/bin/ghc-stage2 --interactive +RTS -s 11,132,224,952 bytes allocated in the heap 1,004,238,408 bytes copied during GC 185,091,216 bytes maximum residency (14 sample(s)) 2,813,504 bytes maximum slop 365 MB total memory in use (0 MB lost due to fragmentation) Tot time (elapsed) Avg pause Max pause Gen 0 706 colls, 0 par 0.907s 0.906s 0.0013s 0.0125s Gen 1 14 colls, 0 par 0.607s 0.606s 0.0433s 0.2244s TASKS: 4 (1 bound, 3 peak workers (3 total), using -N1) SPARKS: 0 (0 converted, 0 overflowed, 0 dud, 0 GC'd, 0 fizzled) INIT time 0.001s ( 0.000s elapsed) MUT time 20.219s ( 20.493s elapsed) GC time 1.514s ( 1.513s elapsed) EXIT time 0.000s ( 0.005s elapsed) Total time 21.733s ( 22.010s elapsed) Alloc rate 550,585,275 bytes per MUT second Productivity 93.0% of total user, 93.1% of total elapsed $ echo ':load MultiLayerModules' | ../inplace/bin/ghc-stage2 --interactive -keep-tmp-files +RTS -s 4,603,831,672 bytes allocated in the heap 971,623,904 bytes copied during GC 184,019,808 bytes maximum residency (14 sample(s)) 2,262,680 bytes maximum slop 365 MB total memory in use (0 MB lost due to fragmentation) Tot time (elapsed) Avg pause Max pause Gen 0 448 colls, 0 par 0.724s 0.723s 0.0016s 0.0321s Gen 1 14 colls, 0 par 0.621s 0.620s 0.0443s 0.2242s TASKS: 4 (1 bound, 3 peak workers (3 total), using -N1) SPARKS: 0 (0 converted, 0 overflowed, 0 dud, 0 GC'd, 0 fizzled) INIT time 0.001s ( 0.000s elapsed) MUT time 7.966s ( 8.202s elapsed) GC time 1.345s ( 1.344s elapsed) EXIT time 0.000s ( 0.004s elapsed) Total time 9.312s ( 9.550s elapsed) Alloc rate 577,938,762 bytes per MUT second Productivity 85.5% of total user, 85.9% of total elapsed }}} So it's 2x slower and allocates 2.5x more. Profiling pointed to https://phabricator.haskell.org/diffusion/GHC/browse/master/compiler/main/S… We're creating `dont_delete_set` a lot. Looks like this was improved in D3111 recently. -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/13701> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #13864: RTS Stats are recorded without -T
by GHC 26 Jun '17

26 Jun '17

#13864: RTS Stats are recorded without -T -------------------------------------+------------------------------------- Reporter: glguy | Owner: (none) Type: bug | Status: new Priority: normal | Milestone: Component: Runtime | Version: 8.2.1-rc2 System | Keywords: | Operating System: Unknown/Multiple Architecture: | Type of failure: None/Unknown Unknown/Multiple | Test Case: | Blocked By: Blocking: | Related Tickets: Differential Rev(s): | Wiki Page: -------------------------------------+------------------------------------- The GHC.Stats module documents that I need to run my program with -T to generate stats, but I don't seem to need to. Perhaps the documentation is wrong or the stats are being collected when they shouldn't be. This is a regression(?) from GHC 8.0.2 where -T was required. -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/13864> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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Re: [GHC] #8033: add AVX register support to llvm calling convention
by GHC 26 Jun '17

26 Jun '17

#8033: add AVX register support to llvm calling convention -------------------------------------+------------------------------------- Reporter: carter | Owner: (none) Type: task | Status: new Priority: normal | Milestone: Component: Compiler | Version: 7.7 Resolution: | Keywords: SIMD Operating System: Unknown/Multiple | Architecture: | Unknown/Multiple Type of failure: None/Unknown | Test Case: Blocked By: | Blocking: Related Tickets: | Differential Rev(s): Wiki Page: | -------------------------------------+------------------------------------- Changes (by bgamari): * owner: carter => (none) * status: closed => new * resolution: invalid => Comment: Reopening as this still hasn't been done. -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/8033#comment:31> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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Re: [GHC] #8033: add AVX register support to llvm calling convention
by GHC 26 Jun '17

26 Jun '17

#8033: add AVX register support to llvm calling convention -------------------------------------+------------------------------------- Reporter: carter | Owner: carter Type: task | Status: closed Priority: normal | Milestone: Component: Compiler | Version: 7.7 Resolution: invalid | Keywords: SIMD Operating System: Unknown/Multiple | Architecture: | Unknown/Multiple Type of failure: None/Unknown | Test Case: Blocked By: | Blocking: Related Tickets: | Differential Rev(s): Wiki Page: | -------------------------------------+------------------------------------- Changes (by bgamari): * keywords: => SIMD -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/8033#comment:30> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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Re: [GHC] #3557: CPU Vector instructions in GHC.Prim
by GHC 26 Jun '17

26 Jun '17

#3557: CPU Vector instructions in GHC.Prim -------------------------------------+------------------------------------- Reporter: guest | Owner: (none) Type: feature request | Status: new Priority: normal | Milestone: ⊥ Component: Data Parallel | Version: 6.11 Haskell | Resolution: | Keywords: SIMD 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): * keywords: => SIMD -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/3557#comment:50> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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Re: [GHC] #7741: Add SIMD support to x86/x86_64 NCG
by GHC 26 Jun '17

26 Jun '17

#7741: Add SIMD support to x86/x86_64 NCG -------------------------------------+------------------------------------- Reporter: shelarcy | Owner: (none) Type: feature request | Status: new Priority: normal | Milestone: Component: Compiler (NCG) | Version: 7.7 Resolution: | Keywords: SIMD Operating System: Unknown/Multiple | Architecture: Type of failure: Runtime | Unknown/Multiple performance bug | Test Case: Blocked By: | Blocking: Related Tickets: #3557 | Differential Rev(s): Wiki Page: wiki:SIMD | -------------------------------------+------------------------------------- Changes (by bgamari): * keywords: => SIMD * wikipage: => wiki:SIMD -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/7741#comment:11> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #13878: Implement SIMD support in NCG
by GHC 26 Jun '17

26 Jun '17

#13878: Implement SIMD support in NCG -------------------------------------+------------------------------------- Reporter: bgamari | Owner: (none) Type: feature | Status: new request | Priority: normal | Milestone: Component: Compiler | Version: 8.0.1 (NCG) | Keywords: | Operating System: Unknown/Multiple Architecture: | Type of failure: None/Unknown Unknown/Multiple | Test Case: | Blocked By: Blocking: | Related Tickets: Differential Rev(s): | Wiki Page: wiki:SIMD -------------------------------------+------------------------------------- Currently [[SIMD]] is only supported in the LLVM code generator. This is a shame and makes functionality significantly harder to depend upon. -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/13878> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #12412: SIMD things introduce a metric ton of known key things
by GHC 26 Jun '17

26 Jun '17

#12412: SIMD things introduce a metric ton of known key things -------------------------------------+------------------------------------- Reporter: bgamari | Owner: Type: bug | Status: new Priority: low | Milestone: Component: Compiler | Version: 8.0.1 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: -------------------------------------+------------------------------------- In #12357 we were looking at reducing the number of entries in the `knownKeyNames`. This has the potential to improve compiler performance since this set of things is always present in the original name cache, which is often referred to. #12357 reduced the number of elements in `knownKeyNames` from 2017 to 1834. Not a bad improvement. That being said, the SIMD operations introduce nearly four times that number. These include things like `readWord64OffAddrAsWord64X2#`, `indexInt16OffAddrAsInt16X16#`, and `remInt16X16#`. All in all these operations constitute nearly a third of the known key names. I'm not really sure what can be done about this, but I thought it should be noted. -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/12412> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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