[GHC] #9234: Compiled code performance regression
#9234: Compiled code performance regression ------------------------------------+--------------------------------- Reporter: augustss | Owner: Type: bug | Status: new Priority: low | Milestone: Component: Compiler | Version: 7.8.2 Keywords: | Operating System: Windows Architecture: Unknown/Multiple | Type of failure: None/Unknown Difficulty: Unknown | Test Case: Blocked By: | Blocking: Related Tickets: | ------------------------------------+--------------------------------- Upgrading from ghc 7.2 to 7.8 has slowed down our main application noticeably. This is with 32-bit Windows. Here's some 7.2 numbers: {{{ INIT time 0.00s ( 0.00s elapsed) MUT time 287.78s (290.41s elapsed) GC time 87.39s ( 88.43s elapsed) EXIT time 0.00s ( 0.00s elapsed) Total time 375.63s (378.86s elapsed) }}} And corresponding 7.8 numbers: {{{ INIT time 0.00s ( 0.00s elapsed) MUT time 298.34s (301.35s elapsed) GC time 88.16s ( 89.27s elapsed) EXIT time 0.00s ( 0.00s elapsed) Total time 386.93s (390.62s elapsed) }}} This is not unexpected since every ghc upgrade so far has slowed down out code; it's just following the trend we expect. -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/9234 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler
#9234: Compiled code performance regression ---------------------------------+------------------------------------ Reporter: augustss | Owner: Type: bug | Status: new Priority: low | Milestone: Component: Compiler | Version: 7.8.2 Resolution: | Keywords: Operating System: Windows | Architecture: Unknown/Multiple Type of failure: None/Unknown | Difficulty: Unknown Test Case: | Blocked By: Blocking: | Related Tickets: ---------------------------------+------------------------------------ Comment (by simonpj): I'm more surprised about this. Generally I expect runtime performance to improve, not get worse. I do profile runtime performance more carefully, but my only benchmark suite is nofib. Anything you can do to characterise what is slowing down would be extremely helpful. Providing benchmark programs would be extremely helpful. Lacking either, and I know that both are hard for you, it's hard to know how to help. Simon -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/9234#comment:1 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler
#9234: Compiled code performance regression ---------------------------------+------------------------------------ Reporter: augustss | Owner: Type: bug | Status: new Priority: low | Milestone: Component: Compiler | Version: 7.8.2 Resolution: | Keywords: Operating System: Windows | Architecture: Unknown/Multiple Type of failure: None/Unknown | Difficulty: Unknown Test Case: | Blocked By: Blocking: | Related Tickets: ---------------------------------+------------------------------------ Comment (by tibbe): Could you set up a build bot the builds GHC HEAD and runs your application using it? That way we could better pinpoint when we regress. GHC should of course have such a build bot itself, using some benchmark suite. -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/9234#comment:2 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler
#9234: Compiled code performance regression ---------------------------------+------------------------------------ Reporter: augustss | Owner: Type: bug | Status: new Priority: low | Milestone: Component: Compiler | Version: 7.8.2 Resolution: | Keywords: Operating System: Windows | Architecture: Unknown/Multiple Type of failure: None/Unknown | Difficulty: Unknown Test Case: | Blocked By: Blocking: | Related Tickets: ---------------------------------+------------------------------------ Description changed by augustss: Old description:
Upgrading from ghc 7.2 to 7.8 has slowed down our main application noticeably. This is with 32-bit Windows.
Here's some 7.2 numbers: {{{ INIT time 0.00s ( 0.00s elapsed) MUT time 287.78s (290.41s elapsed) GC time 87.39s ( 88.43s elapsed) EXIT time 0.00s ( 0.00s elapsed) Total time 375.63s (378.86s elapsed) }}}
And corresponding 7.8 numbers: {{{ INIT time 0.00s ( 0.00s elapsed) MUT time 298.34s (301.35s elapsed) GC time 88.16s ( 89.27s elapsed) EXIT time 0.00s ( 0.00s elapsed) Total time 386.93s (390.62s elapsed) }}}
This is not unexpected since every ghc upgrade so far has slowed down out code; it's just following the trend we expect.
New description: Upgrading from ghc 7.6 to 7.8 has slowed down our main application noticeably. This is with 32-bit Windows. Here's some 7.2 numbers: {{{ INIT time 0.00s ( 0.00s elapsed) MUT time 287.78s (290.41s elapsed) GC time 87.39s ( 88.43s elapsed) EXIT time 0.00s ( 0.00s elapsed) Total time 375.63s (378.86s elapsed) }}} And corresponding 7.8 numbers: {{{ INIT time 0.00s ( 0.00s elapsed) MUT time 298.34s (301.35s elapsed) GC time 88.16s ( 89.27s elapsed) EXIT time 0.00s ( 0.00s elapsed) Total time 386.93s (390.62s elapsed) }}} This is not unexpected since every ghc upgrade so far has slowed down out code; it's just following the trend we expect. -- -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/9234#comment:3 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler
#9234: Compiled code performance regression ---------------------------------+------------------------------------ Reporter: augustss | Owner: Type: bug | Status: new Priority: low | Milestone: Component: Compiler | Version: 7.8.2 Resolution: | Keywords: Operating System: Windows | Architecture: Unknown/Multiple Type of failure: None/Unknown | Difficulty: Unknown Test Case: | Blocked By: Blocking: | Related Tickets: ---------------------------------+------------------------------------ Comment (by augustss): I did try to profile two different ghc versions another time to find out what happened, but the profile is very "smeared out", i.e., many things using a little time. The previous time I tried there was nothing that stuck out; everything just got a little slower. The trend is fairly consistent, we lose 3-10% performance on every ghc upgrade. -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/9234#comment:4 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler
#9234: Compiled code performance regression ---------------------------------+------------------------------------ Reporter: augustss | Owner: Type: bug | Status: new Priority: low | Milestone: Component: Compiler | Version: 7.8.2 Resolution: | Keywords: Operating System: Windows | Architecture: Unknown/Multiple Type of failure: None/Unknown | Difficulty: Unknown Test Case: | Blocked By: Blocking: | Related Tickets: ---------------------------------+------------------------------------ Comment (by augustss): If we had more resources (human and machine) it would be interesting to keep up with ghc HEAD. But keeping up with ghc is not effortless nor automatic. I've spent about 1.5 weeks upgrading from 7.6 to 7.8. It involves finding a set of packages that compiles with the new ghc, and fixing all the places in our code where the new ghc is incompatible with the old one. Note, I'm not complaining about having to do these changes, but we don't have the resources to do them continuously. -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/9234#comment:5 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler
#9234: Compiled code performance regression ---------------------------------+------------------------------------ Reporter: augustss | Owner: Type: bug | Status: new Priority: low | Milestone: Component: Compiler | Version: 7.8.2 Resolution: | Keywords: Operating System: Windows | Architecture: Unknown/Multiple Type of failure: None/Unknown | Difficulty: Unknown Test Case: | Blocked By: Blocking: | Related Tickets: ---------------------------------+------------------------------------ Description changed by augustss: Old description:
Upgrading from ghc 7.6 to 7.8 has slowed down our main application noticeably. This is with 32-bit Windows.
Here's some 7.2 numbers: {{{ INIT time 0.00s ( 0.00s elapsed) MUT time 287.78s (290.41s elapsed) GC time 87.39s ( 88.43s elapsed) EXIT time 0.00s ( 0.00s elapsed) Total time 375.63s (378.86s elapsed) }}}
And corresponding 7.8 numbers: {{{ INIT time 0.00s ( 0.00s elapsed) MUT time 298.34s (301.35s elapsed) GC time 88.16s ( 89.27s elapsed) EXIT time 0.00s ( 0.00s elapsed) Total time 386.93s (390.62s elapsed) }}}
This is not unexpected since every ghc upgrade so far has slowed down out code; it's just following the trend we expect.
New description: Upgrading from ghc 7.6 to 7.8 has slowed down our main application noticeably. This is with 32-bit Windows. Here's some 7.2 numbers: {{{ INIT time 0.00s ( 0.00s elapsed) MUT time 287.78s (290.41s elapsed) GC time 87.39s ( 88.43s elapsed) EXIT time 0.00s ( 0.00s elapsed) Total time 375.63s (378.86s elapsed) }}} And corresponding 7.8 numbers: {{{ INIT time 0.00s ( 0.00s elapsed) MUT time 298.34s (301.35s elapsed) GC time 88.16s ( 89.27s elapsed) EXIT time 0.00s ( 0.00s elapsed) Total time 386.93s (390.62s elapsed) }}} This is not unexpected since every ghc upgrade so far has slowed down our code; it's just following the trend we expect. -- -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/9234#comment:6 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler
#9234: Compiled code performance regression -------------------------------------+------------------------------------- Reporter: augustss | Owner: Type: bug | Status: closed Priority: low | Milestone: Component: Compiler | Version: 7.8.2 Resolution: duplicate | Keywords: Operating System: Windows | Architecture: Type of failure: Runtime | Unknown/Multiple performance bug | Test Case: Blocked By: | Blocking: Related Tickets: | Differential Revisions: -------------------------------------+------------------------------------- Changes (by thomie): * status: new => closed * failure: None/Unknown => Runtime performance bug * resolution: => duplicate Comment: There are currently 184 [https://ghc.haskell.org/trac/ghc/query?status=!closed&failure=Runtime+performance+bug open tickets] concerning runtime performance. Since this one is the least actionable (doesn't have any code attached), I'm going to go ahead and close it. nofib benchmark results are posted on https://perf.haskell.org/ghc/ nowadays, and the issue tracker is at https://github.com/nomeata/gipeda/issues. -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/9234#comment:7 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler
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